8:30 – 10:00 
Registration 
The registration takes place inside the Miramar Palace 
10:00 – 10:15 
Welcome 
Welcome & brief talk about the Donostia International Physics Center (DIPC) 
10:15 – 10:50 
Ramon Aguado 
In my talk, I will argue that nanowirebased hybrid superconductorsemiconductor Josephson junctions are extremely useful platforms to study Majorana physics beyond local transport spectroscopy experiments (“zero bias anomalies”). Physical quantities that provide relevant information about Majorana zero modes in such junctions include ac Josephson currents [1], multiple Andreev reflection [2], critical current measurements [3] and ac susceptibility [4]. Nanowirebased Josephson junctions [5] with sizable charging energy are another novel platform where the physics of standard superconducting qubits in the socalled transmon regime acquires a new twist owing to the presence of Majorana zero modes and lowenergy quasiparticle excitations in the junction [6]. In particular, I will discuss how the presence of lowenergy quasiparticles and Majoranas affects the spectrum of the transmon qubit.
References: 
10:50 – 11:50 
COFFEE BREAK 

11:50 – 12:25 
Roman Lutchyn 
We consider a new model system supporting Majorana zero modes based on semiconductor nanowires with a full superconducting shell. We demonstrate that, in the presence of spinorbit coupling in the semiconductor induced by a radial electric field, the winding of the superconducting order parameter leads to a topological phase supporting Majorana zero modes. The topological phase persists over a large range of chemical potentials and can be induced by a predictable and weak magnetic field piercing the cylinder. The system can be readily realized in semiconductor nanowires covered by a full superconducting shell, opening a pathway for realizing topological quantum computing proposals. 
12:25 – 13:00 
Jelena Klinovaja 
In my talk, I will discuss lowdimensional condensed matter systems, in which topological properties could be engineered per demand. Majorana fermions can emerge in hybrid systems with proximityinduced superconducting pairing. I will present our numerical and analytical studies of such geometries with proximity effects [13]. In the second part of the talk, I will discuss an analytical model of a Rashba nanowire that is partially covered by and coupled to a thin superconducting layer, where the uncovered region of the nanowire forms a quantum dot [4,5]. Even if there is no topological superconducting phase possible, there is a trivial Andreev bound state that becomes pinned exponentially close to zero energy as a function of magnetic field strength when the length of the quantum dot is tuned with respect to its spinorbit length such that a resonance condition of FabryPerot type is satisfied. In this case, the Andreev bound state remains pinned near zero energy for Zeeman energies that exceed the characteristic spacing between Andreev bound state levels but that are smaller than the spinorbit energy of the quantum dot. Importantly, as the pinning of the Andreev bound state depends only on properties of the quantum dot, this behavior is unrelated to topological superconductivity. References: 
13:00 – 15:00 
LUNCH 
Lunch at Costa Vasca at 13:15 
15:00 – 15:35 
Yuval Oreg 
Strong Coulomb interactions may induce a phase transition between a topological superconductor and an insulator. We find that there are several possible insulating phases of topological superconductors, dual (equivalent) to certain spin liquid phases. They include phases with non Abelian particles that may support universal quantum computation. We will discuss possible way to stabilize these exotic phases by interactions between Majoranazero modes in a Cooper box. In particular we will show how a critical supersymmetric state emerges. 
15:35 – 15:55 
Katharina Laubscher 
We consider a system of weakly coupled Rashba nanowires in the strong spinorbit interaction (SOI) regime. The nanowires are arranged into two tunnelcoupled layers proximitized by a top and bottom superconductor such that the superconducting phase difference between them is π. We show that in such a system strong electronelectron interactions can stabilize a helical topological superconducting phase hosting Kramers partners of Z_2m parafermion edge modes, where m is an odd integer determined by the position of the chemical potential. Furthermore, upon turning on a weak inplane magnetic field, the system is driven into a secondorder topological superconducting phase hosting zeroenergy Z_2m parafermion bound states localized at two opposite corners of a rectangular sample. As a special case, zeroenergy Majorana corner states emerge in the noninteracting limit m = 1, where the chemical potential is tuned to the SOI energy of the single nanowires. 
15:55 – 16:30 
Björn Trauzettel 
Parafermions are generalizations of Majorana fermions that emerge in interacting topological systems. They are known to be powerful building blocks of topological quantum computers. Existing proposals for realizations of parafermions typically rely on strong electronic correlations which are difficult to achieve in the laboratory. We identify a novel physical system in which parafermions develop. It is based on a quantum point contact (QPC) formed by the helical edge states of a quantum spin Hall insulator (QSHI) in vicinity to an ordinary swave superconductor. Interestingly, our analysis suggests that Z4 parafermions are emerging bound states in this setup even in the weakly interacting regime. Furthermore, we identify conditions under which parafermions and Majorana fermions coexist [1]. Additionally, we present recent transport measurements through a QPC formed in a QSHI. An intriguing conductance quantization is observed which indicates spontaneous breaking of timereversal symmetry by electronic correlations [2]. References: 
16:30 – 17:00 
COFFEE BREAK 

17:00 – 17:35 
Enrique Ortega 
Tailoring electron scattering at surfaces is of key importance to develop topological materials for spintronics. For example, spinpolarized currents could be sustained at the surface through Rashbasplit states, since these are topologically protected against backscattering at surface defects, such as atomic steps. In this context, we aim at probing electron scattering at steps by combining curved crystal surfaces and Angle Resolved Photoemission. By employing curved crystals with selected azimuthal direction we achieve tunable arrays of monoatomic steps with different morphology and orientations. Scanning the ultraviolet light beam on the curved surface during angleresolved photoemission experiments we unveil the scattering behavior of surface states. The fundamental ideas are tested with noble metal surfaces and Shockley states, which exhibit a variable scattering strength and exotic chargedensitywavelike electronic/structural interplays. Finally, I will present the first realization of periodic step arrays on the BiAg2 atomthick surface alloy, with unprecedented atomic precision, and demonstrate their potential for tuning helical Rashba states. 
9:15 – 9:50 
Daniel RodanLegrain 
The understanding of stronglycorrelated quantum matter has challenged physicists for decades. Such difficulties have stimulated new research paradigms, such as ultracold atom lattices for simulating quantum materials. In this talk I will present a new platform to investigate strongly correlated physics, based on graphene moiré superlattices. In particular, when two graphene sheets are twisted by an angle close to the theoretically predicted ‘magic angle’, the resulting flat band structure near the Dirac point gives rise to a stronglycorrelated electronic system. These flat bands exhibit halffilling insulating phases at zero magnetic field, which we show to be a correlated insulator arising from electrons localized in the moiré superlattice. Moreover, upon doping, we find electrically tunable superconductivity in this system, with many characteristics similar to hightemperature cuprates superconductivity. These unique properties of magicangle twisted bilayer graphene open up a new playground for exotic manybody quantum phases in a 2D platform made of pure carbon and without magnetic field. Since these discoveries, a large number of theoretical models have been proposed based on the magicangle graphene superlattices and beyond. I will also discuss our data demonstrating nematicity in the superconducting state, strange metal behavior at correlated fillings with near Planckian dissipation as well as correlated states in other types of graphene superlattices. The easy accessibility of the flat bands, the electrical tunability, and the bandwidth tunability through twist angle may pave the way towards more exotic correlated systems, such as quantum spin liquids. 
09:50 – 10:25 
Niels Walet 
In this talk I will discuss the behaviour of twisted bilayer graphene, and particularly its lattice relaxation and the effect on its electronic structure. Based on a tight binding model, we develop a generic approach to the construction of continuum models. Due to the small local deformation of the graphene lattice, we find that this approach can be applied for any sensible model of the interlayer hopping, and reproduce the result of rather expensive tightbinding calculations. We study the effects on near magicangle bilayers (in the order of 1 degree of twist), and marginal angles, where networks of onedimensional channels emerge. 
10:25 – 11:15 
COFFEE BREAK 

11:15 – 11:50 
Klaus Ensslin 

11:50 – 12:25 
Richard Warburton 
We report a spontaneous spinpolarisation in a twodimensional electron gas in monolayer MoS_{2} [1]. In a twodimensional electron gas (2DEG), Coulomb effects dominate over singleparticle effects in the limit of low electrondensity. In this regime, the average interelectron distance is larger than the Bohr radius in the host material. In gallium arsenide and silicon 2DEGs, electrons are localized at these low electron densities such that Coulomb effects tend to be obscured. New opportunities arise in transitionmetal dichalcogenides (TMDs). A TMD represents a natural realization of a 2DEG. Significantly, the extremely small Bohr radius in a TMD suggests that Coulomb effects play an important role at experimentally relevant electrondensities. We probe the electronic groundstate of a gated monolayer of MoS_{2} at various electron densities using optical absorption, a local, noninvasive, spin and valleyresolved tool. In a singleparticle picture, we expect the groundstate to be formed by a closetoequal filling of the four available conduction bands. Our experiment overturns this singleparticle picture: only two of the four bands are occupied – the two with the same spin but at different valleys. This is a striking result: the creation of a spontaneous spinpolarisation in a 2DEG. We propose that intervalley electronelectron exchange is responsible for the creation of a spin polarised groundstate in electrondoped monolayer MoS2. Even though the K and K ́ points are far apart in phasespace, the Bohr radius is so small that intervalley Coulomb scattering is significant. This work was carried out in the NanoPhotonics Group in the Department of Physics, University of Basel, together with Jonas G. Roch, Guillaume Froehlicher and Nadine Leisgang. Complementary theoretical work was carried out by Dmitry Miserev, Jelena Klinovaja, and Daniel Loss [2]. References: 
12:25 – 12:45 
Dmitry Miserev 
Atomically thin layers of transition metal dichalcogenides (TMDs) such as MoS2 are twovalley materials that attract more and more attention as a promising candidates for valleytronics. Relatively large spinorbit interaction provides valleydependent selection rules for optical experiments allowing the optical control of the valley polarization of 2D electron gas at small densities. However, the single particle picture is not always true. Here we present our work where we predict the first order Ising ferromagnetic phase transition coming from the electronelectron interaction. We show that the spontaneous valley and spinvalley polarization cannot develop due to the effect of the exchange inter valley scattering which is strong in TMDs. The first order nature of the ferromagnetic phase transition comes from the nonanalytic cubic terms in the thermodynamic potential. The spinorbit interaction breaks the O(3) symmetry of the ferromagnet resulting in the Ising order. Our prediction is consistent with the recent optical experiment [J. G. Roch et al., published online in Nature Nanotech. (2019), arXiv:1807.06636] where the Ising ferromagnetic phase has been detected. 
12:45 – 13:05 
Sadashige Matsuo 
Recently it has become possible to look more closely thermodynamics in the single electron tunneling process because the devices of study hold improved capability of controlling and detecting the electron tunneling events and therefore the charge transport dynamics can be traced in real time. Then the fundamental statistics of the electrons has been revealed and thermodynamics rules such as the fluctuation theorem has been demonstrated. However, to date most of the experimental studies have concentrated on the charge degree of freedom but not the spin degree of freedom. On the other hand, spin measurement techniques have been well improved for electrons in quantum dots, and can apply for study on the fundamental statistics. Indeed various spinrelated phenomena have been unveiled for the Pauli spin blockade (PSB) effect in quantum dots, including the peculiar time traces associated with lifting PSB, the spinflip tunnel rates and the microscopic mechanism of the spinflip events. Here we report on a theoretical and experimental study of the full counting statistics (FCS) for electron spins in the PSB on a GaAs gatedefined double quantum dot. The FCS is a probability density as a function of the charge transition number, and can provide important information about the statistics of the dynamics because it contains a lot of statistical information such as allorder of the cumulants. First, we evaluated all of the necessary tunnel rates to construct the FCS from the time traces and then constructed the FCS and compared it to our theoretical result. We found that there are two peculiar features, the asymmetric shape of the probability density and the parity effect about the transition number. We will discuss these origins using our theoretical model. These results are the first experimental results of the FCS for the spinrelated phenomenon and provide a useful tool for revealing the dynamics of spins in the multiple quantum dots. 
13:05 – 15:00 
LUNCH 
Lunch at Costa Vasca at 13:15 
15:00 – 15:35 
Hector Ochoa 
Van der Waals materials are formed from weakly interacting and mechanically stiff atomic layers. Sliding and twisting these layers with respect to each other give rise to superstructures with emergent functionalities like, for example, the plethora of strongly correlated phenomena (superconductivity included) observed in twisted bilayer graphene. One of the most recent development on this front the observation of a remarkably large, linear in temperature (T) resistivity in the normal state. Some theories have attributed this behavior to electronphonon scattering. In this talk, I will argue that the longwavelength dynamics of these generically incommensurate structures are dominated by new collective modes, phasons [1]. These modes correspond to coherent superpositions of optical phonons describing the sliding motion of stacking solitons separating regions of partial commensuration. I will illustrate this physics with recent data acquired in MoSe2 multilayers [2], where scanning tunnel microscopy revealed the formation of stacking textures above some critical strain with distinct imprints in tunnel spectroscopy. I will also show that when interlayer forces are taken into account, transverse phason modes of twisted bilayer graphene dominate the interaction of electrons with the lattice. This coupling lifts the layer degeneracy of the reconstructed Dirac cones, which could explain the observed 4fold (instead of 8fold) Landau level degeneracy in magnetotransport. Electronphason scattering gives rise to a linearT contribution to the resistivity that increases with decreasing twist angle due to the reduced rigidity of the Moiré pattern. This contribution, however, seems to be insufficient to explain the rapid increase of the resistivity close to the magic angle condition. These results point to a different mechanism, possibly related to a Fermisurface reconstruction linked to the correlated phenomena at lower temperatures. References: 
15:35 – 16:10 
Gloria Platero 
The effect of ac electric fields on the transport properties of low dimensional systems has been a topic of intense research in the last years. Applying ac electric fields to coupled quantum dots allows to transfer charge between them by means of photoassisted transitions. Experiments in triple quantum dots unambiguously show direct electron transfer between the outer dots, without the participation of the intermediate region other than virtual, thus minimizing the effect of decoherence and relaxation [13]. In the presence of ac driving the transfer of electrons between distant dots takes place by means of photoassisted virtual transitions [35]. A review on the theoretical models and experimental evidence of long range charge and quantum state transfer in ac driven quantum dot arrays will be provided. I will focus on a protocol for preparing a quantum state at the left edge of a triple quantum dot and directly transferring it to the right edge by means of ac gate voltages. I will show that by the controlled generation of dark states it is possible to increase the fidelity of the transfer protocol [6]. I will discuss as well other protocols which allow for long range charge transfer as coherent transfer by adiabatic passage (CTAP)[7]. Adiabatic protocols however, provide slow transfer prone to decoherence. I will show how these protocols can be speeded up by shortcuts of adiabaticity [8]. Furthermore, it allows for long range transfer of two electron entangled states in longer quantum dot arrays with high fidelity [11]. The proposed protocols offer an alternative and robust mechanism for quantum information processing. Finally I will discuss how to implement the SSH model in a quantum dot array, the role of edge states in the electron dynamics and how the presence of an ac electric field allows to detect the topological phases by transport measurements[1011]. References: 
16:10 – 16:45 
Dominik Zumbühl 
We show that inplane magneticfieldassisted spectroscopy allows extraction of the inplane orientation and full 3D size parameters of the quantum mechanical orbitals of a single electron GaAs lateral quantum dot with subnanometer precision. The method is based on measuring the orbital energies in a magnetic field with various strengths and orientations in the plane of the 2D electron gas. From such data, we deduce the microscopic confinement potential landscape and quantify the degree by which it differs from a harmonic oscillator potential. The spectroscopy is used to validate shape manipulation with gate voltages, agreeing with expectations from the gate layout. Our measurements demonstrate a versatile tool for quantum dots with one dominant axis of strong confinement. 
16:45 – 19:00 
POSTER SESSION 
9:15 – 9:50 
Roland Wiesendanger 
The ability to construct nanoscale systems with atomiclevel precision by using STMbased singleatom manipulation techniques has led to numerous outstanding examples of Quantum Designer Physics. In particular the combination of singleatom manipulation with spin sensitive imaging and spectroscopy based on the spinpolarized STM technique [1] offers an exciting approach towards the design of specific properties of 1D spin chains [2] as well as 2D arrangements of tailored nanomagnets [3]. Investigating such artificially built spin arrays on superconductor surfaces has recently led to the observation of Majorana zeroenergy modes in atomically welldefined magnetsuperconductor hybrid systems [4]. Moreover, prototypes for allspin atomicscale spin logic devices could be demonstrated by a bottomup fabrication technique [5]. In this talk, the focus will be on the tailoring of the spin dynamics of artificially built atomic arrangements on surfaces, such as fewatom clusters or 2D spin arrays. Making use of time and spinresolved STM techniques [6] we will show how the spin dynamics can be tuned by the choice of the substrate, the chemical identity and number of the adatoms as well as their geometric arrangement [79]. In particular it will be demonstrated that the symmetry of the adatom arrangements can have a decisive influence on the spin dynamics. This can be explained by the effect of anisotropic indirect exchange interactions which can lead to a destabilization of the spin system for atomic arrangements exhibiting a lower symmetry [9]. References: 
09:50 – 10:25 
Sebastian Bergeret 
We demonstrate that the interplay of Zeeman and spinorbit coupling fields in a 1D wire leads to an equilibrium spin current that manifests itself in a spin accumulation at the wire ends with a polarization perpendicular to both fields. This is a universal property that occurs in the normal and superconducting state independently of the degree of disorder. We find that the edge spin polarization transverse to the Zeeman field is strongly enhanced in the superconducting state when the Zeeman energy is of the order of the superconducting gap. By calculating the space resolved magnetization response of the wire we demonstrate that the transverse component of the spin at the wire edges can be much larger than the one parallel to the field. This result generalizes the well established theory of the Knightshift in superconductors to the case of finite systems. 
10:25 – 11:15 
COFFEE BREAK 

11:15 – 11:50 
Christian Schönenberger 
In this presentation I will review our recent experiments on semiconducting nanowires (NWs) and carbon nanotubes (CNTs) in close proximity to one or two superconducting contacts. To perform wellcontrolled transport spectroscopy in such systems, we introduce two new device types, namely InAs NWs with atomically precise crystal phase engineered insitu grown axial tunnel barriers, and CNTs fully encapsulated in hexagonal Boron Nitride, both contacted by bulk superconductors. In the latter devices we obtain very long and clean quantum dots, with multiple subgap states and a nonmonotonic magnetic field dependence of the critical supercurrent. For the NW systems, we use the axial tunnel barriers to probe, for example, the formation of the superconducting proximity gap in a long NW segment, or the hybridization of Andreevtype bound states (ABSs) with quantum dot states. We also have studied the ABSs spectroscopically in magnetic field. We believe that these device architectures will be crucial for investigating and characterizing the large variety of new topologically trivial and nontrivial subgap states expected to form in such systems. Acknowledgment: This work has been done by the following list of contributors in alphabetic order: G. Abulizi, A. Baumgartner, D. Chevallier, R. Delagrange, K. A. Dick, O. Faist, G. Fülöp, R. Haller, C. Jünger, S. Lehmann, M. Nilsson, A. Pally, J. Ridderbos, L. Sorba, T. Taniguchi, C. Thelander, J. Ungerer, K. Watanabe and V. Zannier. I am very grateful to them! The work has financially been supported by the Swiss NSF, SNFQSIT, SNI, H2020 project QuantEra SuperTop and FETopen AndQC. 
11:50 – 12:25 
Patrik Recher 
Majorana bound states (MBSs) are nonAbelian quasiparticles in vortices of topological superconductors. They have been identified as building blocks for topologically protected qubits where quantum state evolution within a degenerate ground state manifold proceeds via braiding of distant MBSs. We present a theory of coherent timedependent electron tunneling from a metal tip into a Corbino geometry topological Josephson junction where four MBSs rotate. The time averaged tunneling conductance exhibits, as a function of bias voltage between the tip and the Josephson junction, distinctive conductance peaks that are separated by h/(4TJ) (where TJ is the time period of the system Hamiltonian). This separation is a result of interference between processes where electron tunneling between the tip and the junction interrupts the rotation of the MBS after different number of round trips. The interference effect is shown to be a direct consequence of two noncommuting braiding operationsa rotation of the four MBSs along the Josephson junction and a tunneling assisted rotationreflecting the nonAbelian nature of MBSs. This mechanism of nonAbelian state evolution actively utilizes electron tunneling that changes the fermion occupation number parity of the system rather than avoiding it while the MBSs are spatially decoupled from each other and hence are not fused physically. The proposed scheme would provide an alternative route for detecting non Abelian statistics.

12:25 – 13:00 
Maria A. Vozmediano 
The coupling of lattice deformations to electronic properties in graphene the most popular Dirac material as gauge fields has given rise to a vast field of theoretical, experimental results and applications. In this talk we will review the situation in the novel 3D Dirac semimetals with especial focus on the interplay between strain and and the chiral and gravitational anomalies. 
13:00 – 15:00 
LUNCH 
Lunch at Costa Vasca at 13:15 
15:00 – 15:35 
DeungJang Choi 
Recently, the introduction of impurity states in the superconducting gap has received a lot of attention. Indeed, the search of a new superconducting state called topological superconductivity is strongly based in the combination of doping classical (swave) superconductors with magnetic impurities that arrange spins in a chiral fashion. Magnetic adatoms can be considered as impurities that weaken the binding of superconducting Cooper pairs leading to impurity levels in the gap: socalled Yu ShibaRusinov (YSR) states. By using scanning tunneling microscopy (STM), we study magnetic impurities on superconducting surfaces revealing the orbital properties of the YSR states associated with them [1]. We also present the first results of controlled singleatom manipulation to assemble a chain of Cr atoms on a Bi2Pd superconductor. The influence of the atoms on the superconducting electronic structure is revealed as well as the interactions at work. The dependence of the electronic structure on the interatomic distance between two Cr atoms is thoroughly explored revealing CrCr interactions mediated by the superconductor for the first time [2]. Such magnetic impurities on different substrates allow us to explore many body effects and exotic phenomena in different experimental spin systems giving an understanding on the parameters on each system. References: 
15:35 – 16:10 
Jairo Sinova 
The effective manipulation of antiferromagnets (AF), through the recently proposed and discovered Néel spinorbit torque, has turned AFM into active elements of spintronic devices. This, coupled with the inherent topological properties of their bandstructure, makes topological antiferromagnetic spintronics a fruitful area of exploration. A key remaining challenging aspect is the observation of the Néel order parameter. Here we show that the anomalous Hall effect can play a key role, which over a century, continue to play a central role in condensed matter research for their intriguing quantummechanical, relativistic, and topological nature. Here we introduce a microscopic mechanism whose key component is an asymmetric spinorbit coupling originating from lowered symmetry positions of atoms in the crystal. Based on firstprinciples calculations, we demonstrate a pristine form of this crystal Hall effect in a roomtemperature rutile antiferromagnet RuO2 whose Hall conductivity reaches 1000 S/cm. While a collinear antiferromagnetic order of magnetic moments alone would generate zero Hall response, the effect arises when combining it with the spinorbit coupling due to nonmagnetic atoms occupying noncentrosymmetric crystal positions. The crystal Hall effect can also explain recent measurements in a chiral antiferromagnet CoNb3S6, and we predict it in a broad family of collinear antiferromagnets.

16:10 – 16:45 
María BlancoRey 
The DzyaloshinskiiMoriya interaction (DMI) has its origin in the spinorbit correction of the Heisenberg exchange interactions. It is a rankone firstorder effect that favours canting of neighbouring spins and it is thus one of the interactions that govern longrange noncollinear spin textures. The DMI is behind the chirality of spin spirals that leads magnetic domain wall movement [1]. Since the DMI is forbidden by inversion symmetry, it often appears localized at surfaces and interfaces. Moreover, in multilayer heterostructures the interactions present at each interface are combined additively [2]. This property opens the door to controlling the chirality of domain wall displacement at selected buried interfaces by epitaxial growth. For example, experiments suggest that the strong DMI at a Pt/Co interface may be nearly halved if the Co film is (pseudomorphically) grown by intercalation between Pt and graphene [3]. In this talk I will show how the principle of additivity of interfacial DMI breaks down in the limit of ultrathin films. Taking the Pt/Co/Graphene heterostructure as case study, we have carried out DFT calculations of spin spirals [4] and obtained the interatomic DMI vectors, D, by fitting a model hamiltonian. We find that the inplane component of D has a nontrivial oscillatory behaviour up to 3ML of Co, which is likely to modulate the Néeltype domain wall velocity. Interestingly, we find a significant outofplane component of D, compatible with a more complex chiral spin structure. References: 
16:45 – 17:15 
COFFEE BREAK 

17:15 – 17:50 
Evgueni Chulkov 

17:50 – 18:10 
María Belén Farias 
We develop the theory of quantum friction in twodimensional topological materials. The quantum drag force on a metallic nanoparticle moving above such systems is sensitive to the nontrivial topology of their electronic phases, shows a novel distance scaling law, and can be manipulated through doping or via the application of external fields. We use the developed framework to investigate quantum friction due to the quantum Hall effect in magnetic field biased graphene, and to topological phase transitions in the graphene family materials. It is shown that topologically nontrivial states in twodimensional materials enable an increase of two orders of magnitude in the quantum drag force with respect to conventional neutral graphene systems. 
18:10 – 18:30 
Mikhail Otrokov 
Magnetic proximity effect at the interface between magnetic and topological insulators (MIs and TIs) is considered to have great potential in spintronics as, in principle, it allows realizing the quantum anomalous Hall and topological magnetoelectric effects (QAHE and TME). Although an outofplane magnetization induced in a TI by the proximity effect was successfully probed in experiments, firstprinciples calculations reveal that a strong electrostatic potential mismatch at abrupt MI/TI interfaces creates harmful trivial states rendering both the QAHE and TME unfeasible in practice. Here on the basis of recent progress in formation of planar selfassembled single layer MI/TI heterostructure [1], we propose a conceptually new type of the MI/TI interfaces by means of density functional theory calculations [2]. By considering MnSe/Bi2Se3, MnTe/Bi2Te3, and EuS/Bi2Se3 we demonstrate that, instead of a sharp MI/TI interface clearly separating the two subsystems, it is energetically far more favorable to form a builtin interface via insertion of the MI film inside the TI’s surface quintuple layer (e.g., Se–Bi–Se–[MnSe]–Bi–Se) where it forms a bulklike MI structure. This results in a smooth MItoTI connection that yields the interface electronic structure essentially free of trivial states. Our findings open a new direction in studies of the MI/TI interfaces and restore their potential for the QAHE and TME observation. The supports by the Spanish Ministerio de Economia y Competitividad (FIS201675862P), Academic D.I. Mendeleev Fund Program of Tomsk State University (8.1.01.2018), Saint Petersburg State University grant for scientific investigations (15.61.202.2015), and Fundamental Research Program of the State Academies of Sciences, line of research III.23 are acknowledged. References: 
20:30 – 23:00 
CONFERENCE DINNER 
Restaurante Ni Neu (Address: Zurríola Hiribidea, 1, DonostiaSan Sebastián) See howtogetthere instructions and map 
9:15 – 9:50 
Constantin Schrade 
We introduce and study a minimum twoorbital Hubbard model on a triangular lattice, which captures the key features of both the trilayer ABCstacked grapheneboron nitride heterostructure and twisted transition metal dichalcogenides in a broad parameter range. Our model comprises first and secondnearest neighbor hoppings with valleycontrasting flux that accounts for trigonal warping in the band structure. For the strongcoupling regime with one electron per site, we derive a spinorbital exchange Hamiltonian and find the semiclassical ground state to be a spinvalley density wave. We show that a relatively small secondneighbor exchange interaction is sufficient to stabilize the ordered state against quantum fluctuations. Effects of spin and valley Zeeman fields as well as thermal fluctuations are also examined. 
09:50 – 10:25 
Hadar Steinberg 
The vanderWaals fabrication method allows the realization of novel types of superconducting devices. In our work, we use van der Waals semiconductors as tunnel barriers separating the superconductor NbSe2 and normal counter electrodes. The devices exhibit a hard gap [1], which allows tracking subgap excitations such as vortexbound states [2]. VanderWaals barriers often carry defects, which function as atomicsized quantum dots. We find that in certain cases, a barrier defect may hybridize with the underlying superconductor, and form Andreev bound states (ABS), which are observed as subgap features in tunneling experiments, analogous to ABS observed in nanowires. We take advantage of the special properties of ultrathin NbSe2, where spinorbit coupling keeps the superconducting gap stable upon application of parallel magnetic fields in the few Tesla regime. This gap stability allows the following of subgap features. These are found to split in energy, with a lower branch meeting at zero at a finite field. Such spectral evolution, associated with a singlet ground state, is consistent with a small charging energy. We further describe the observation of zeroenergy states appearing at finite magnetic fields, and discuss their relation to the strong spin orbit term in the system [3]. References: 
10:25 – 11:15 
COFFEE BREAK 

11:15 – 11:50 
Javier Aizpurua 
A nanoscale gap between two metallic nanoparticles is an ideal platform to exploit the interplay between electron currents and photonic excitations. The capability of the metallic gap to enhance the amplitude of the induced plasmonic field produces a variety of nonlinear effects [1] which can be exploited in different applications of optoelectronics, such as optical rectification, light emission driven by DC currents, or highharmonic generation, among others. Furthermore, in ultranarrow gaps, tunneling of electrons at optical frequencies has been found to screen the plasmonic bonding gap resonance, and activate a new distribution of optical modes characterized by optical charge transfer [2]. Here we address the complex dynamics of photoelectrons driven by singlecycle optical pulses in nanoscale gaps. By solving Schrödinger equation within the framework of TimeDependent Density Functional Theory (TDDFT), the currents of the electrons photoemitted across the gap can be monitored, identifying ultrafast electron bursts where electron quiver occurs when the amplitude of the induced field at the plasmonic gap is reversed within the optical cycle. The properties of the amplitude and carrierenvelope phase (CEP) of the incident pulse, together with the gap length determine the complex electron dynamics [3]. Experimental measurements of the current autocorrelations for pairs of such pulses with controlled relative delay between them, confirms the ultrafast dynamics of the photoelectrons in the gap and its complexity. References: 
11:50 – 12:25 
Akira Furusaki 
We revisit the problem of an interacting quantum wire subject to spinorbit interaction and transverse magnetic field. Previous studies showed that the spin sector of the model is equivalent to that of a spin chain with uniform DM interaction (D) in a transverse magnetic field (h), the ground state of which contains two ordered Ising phases and a critical TomonagaLuttinger liquid phase, depending on the ratio D/h. Importantly, the charge sector of the wire is a gapless TomonagaLuttinger liquid. We show that a quantum wire with an open boundary supports a zeroenergy bound state localized at the edge, provided that the spin sector of the problem is massive. We argue that as long as the charge sector is gapless, the wire is in a topological phase and that the bound state is a Majorana zero mode, and discuss physical implications of this finding.

12:25 – 13:00 
Sander Kempkes 
Higherorder topological insulators recently emerged as a new class of materials exhibiting
topologically protected states in at least two dimensions below that of the bulk. In the important
case of electronic 2D higherorder topological insulators, nontrivial 0D corner modes arise which
can accommodate quasiparticles with a fraction of the electron charge. Charge fractionalization is
wellknown for the stronglycorrelated electron systems in the fractional quantum Hall effect and
Luttinger liquids. Here, we experimentally realize quasiparticles with fractional charge in the
absence of electronelectron interactions. Specifically, by carefully tuning the design of an artificial
electronic lattice in a scanning tunneling microscope, we create a higherorder topological insulator
based on the 2D SuSchriefferHeeger (SSH) lattice. Scanning tunneling spectroscopy and
wavefunction mapping reveal protected corner modes that carry a fraction of the unit charge. Our
results provide a first step to incorporate quasiparticles with fractional charge into electronic
devices for quantum computation.

13:00 – 15:00 
LUNCH 
Lunch at Costa Vasca at 13:15 