A5020523597- Quantum and electron transport phenomena
- Graphene research and applications
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Quantum, superfluid, helium dynamics
- High-pressure geophysics and materials
- Electronic and Structural Properties of Oxides
- Cold Atom Physics and Bose-Einstein Condensates
- earthquake and tectonic studies
- 2D Materials and Applications
- Geological and Geochemical Analysis
- Semiconductor Quantum Structures and Devices
- Surface and Thin Film Phenomena
- Magnetic properties of thin films
- Molecular Junctions and Nanostructures
- Diamond and Carbon-based Materials Research
- Quantum many-body systems
- Experimental and Theoretical Physics Studies
- Seismic Imaging and Inversion Techniques
- Perovskite Materials and Applications
- Thermal properties of materials
- Seismic Waves and Analysis
- Strong Light-Matter Interactions
- Experimental Learning in Engineering
University of Zurich
2022-2025
ETH Zurich
2025
University of Oxford
2017-2022
Centre for Policy Studies
2022
University of California, Santa Barbara
2021
Patrick Air Force Base
2010
Office of Chief Medical Examiner
2005
University of Colorado Boulder
2002
Cardiovascular Research Associates
1999
University of South Carolina
1995
We investigate the full doping and strain-dependent phase diagram of normal state magic-angle twisted bilayer graphene (TBG). Using comprehensive Hartree-Fock calculations, we show that at temperatures where superconductivity is absent global structure can be understood based on competition coexistence between three types intertwined orders: a fully symmetric phase, spatially uniform flavor-symmetry-breaking states, an incommensurate Kekulé spiral (IKS) order. For small strain, IKS recently...
In the currently debated context of using clusters galaxies as cosmological probes, need for well-defined cluster samples is critical. The XXL Survey has been specifically designed to provide a well characterised sample some 500 X-ray detected suitable studies. main goal present article make public and describe properties catalogue in its state, associated catalogues super-clusters fossil groups. We release containing 365 total. give details follow-up observations explain procedure adopted...
We study magic angle graphene in the presence of both strain and particle-hole symmetry breaking due to non-local inter-layer tunneling. perform a self-consistent Hartree-Fock that incorporates these effects alongside realistic interaction substrate potentials, explore comprehensive set competing orders including those break translational at arbitrary wavevectors. find all non-zero integer fillings very small strains, comparable measured scanning tunneling experiments, stabilize...
Abstract We develop a regional seismic travel-time (RSTT) model and method for use in routine analysis. The parameterization is global tessellation of nodes with velocity profile at each node. Interpolation the profiles generates 3D crust laterally variable upper-mantle velocity. node represented as linear gradient, which enables computation approximately 1 millisecond. This computational speed allows to be used analyses operational monitoring systems. refine using tomographic formulation...
Topological quantum chemistry (TQC) is a successful framework for identifying (noninteracting) topological materials. Based on the symmetry eigenvalues of Bloch eigenstates at maximal momenta, which are attainable from first principles calculations, band structure can either be classified as an atomic limit, in other words adiabatically connected to independent electronic orbitals respective crystal lattice, or it topological. For interacting systems, there no single-particle and hence, TQC...
Magic-angle twisted bilayer graphene has attracted significant attention for its strongly correlated phenomena. Recent scanning tunneling experiments have measured graphene-scale Kekul\'e charge ordering in some of the insulators and nearby metallic phases. While most these can be explained by strain-induced incommensurate spiral phase, presence ultralow strain devices is unexpected within existing theory. Using Hartree-Fock strong-coupling calculations, authors show that such observations...
Due to the presence of flat Chern bands, moiré transition-metal dichalcogenide (TMD) bilayers are a platform realize strongly correlated topological phases fermions such as fractional insulators. TMDs also known host long-lived excitons, which inherit topology underlying bands. For particular example <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>MoTe</a:mi><a:mn>2</a:mn></a:msub><a:mo>/</a:mo><a:msub><a:mi>WSe</a:mi><a:mn>2</a:mn></a:msub></a:math> heterobilayers we...
We study the excitations that emerge upon doping translationally-invariant correlated insulating states in magic angle twisted bilayer graphene at various integer filling factors $\nu$. identify parameter regimes where these are associated with skyrmion textures spin or pseudospin degrees of freedom, and explore both short-distance pairing effects formation long-range ordered crystals. perform a comprehensive analysis skyrmions insulators even $\nu$, delineating regime space lowest-energy...
Standard superconductors display a ubiquitous discontinuous jump in the electronic specific heat at critical superconducting transition temperature. In growing class of unconventional superconductors, however, second order parameter component may get stabilized and produce capacity lower temperature, typically associated with spontaneous breaking time-reversal symmetry. The splitting two discontinuities can be controlled by external perturbations such as chemical substitution, hydrostatic...
We present the version of point source catalogue XXL Survey that was used, in part, first series papers. In this paper we release, our database Milan and at CDS: (i) X-ray with 26056 objects two areas 25 deg2; (ii) associated multiwavelength catalogues candidate counterparts sources infrared, near-infrared, optical, ultraviolet (plus spectroscopic redshift when available); (iii) a redshifts recently obtained southern area. also basic properties their counterparts. Other described second...
We consider magic-angle twisted bilayer graphene (TBG) at filling $\nu=+3$, where experiments have observed a robust quantized anomalous Hall effect. This has been attributed to the formation of valley- and spin-polarized Chern insulating ground state that spontaneously breaks time-reversal symmetry, is stabilized by hexagonal boron nitride (hBN) substrate. identify three different types domain wall, study their properties energetic selection mechanisms via theoretical arguments Hartree-Fock...
A variational wave function for quantum Hall bilayers at filling factor $\ensuremath{\nu}$=1 with composite-fermion electrons in one layer and holes the other indicates BEC-BCS crossover.
Bilayer quantum Hall states have been shown to be described by a BCS-paired state of composite fermions. However, finding qualitatively accurate model valid across all values the bilayer separation is challenging. Here, we introduce two variational wave functions, each with single parameter, which can thought as proxy for BCS order parameter. Studying systems up $9+9$ electrons in spherical geometry using Monte Carlo methods, show that ground accurately these single-parameter states. In...
Twisted transition metal dichalcogenides (TMDs) host bands with opposite Chern number for the two spin species and could thus be fractional topological insulator states. In multicomponent quantum Hall systems, where spins have equal number, resulting liquid states can well modeled by trial wavefunctions such as Halperin $(lmn)$ wavefunctions. These are exact zero energy of certain short-range (pseudopotential) Hamiltonians. However, we show that a construction fails in case numbers opposite,...
A striking series of experiments have observed superconductivity in Bernal-stacked bilayer graphene (BBG) when the energy bands are flattened by applying an electrical displacement field. Intriguingly, manifests only at non-zero magnetic fields, or spin-orbit coupling is induced BBG to a substrate. We present detailed functional renormalization group and random-phase approximation calculations that provide unified explanation for superconducting mechanism both cases. Both yield purely...
Using the semiclassical quantum Boltzmann equation (QBE), we numerically calculate dc transport properties of bilayer graphene near charge neutrality. We find, in contrast to prior discussions, that phonon scattering is crucial even at temperatures below 40 K. Nonetheless, electron-electron still dominates over collisions allowing a hydrodynamic approach. introduce simple two-fluid model electrons and holes interacting via Coulomb drag compare our results full QBE calculation. show produces...
Step edges of topological crystalline insulators can be viewed as predecessors higher-order topology, they embody one-dimensional edge channels embedded in an effective three-dimensional electronic vacuum emanating from the insulator. Using scanning tunneling microscopy and spectroscopy, we investigate behavior such Pb1-xSnxSe under doping. Once energy position step is brought close to Fermi level, observe opening a correlation gap. The experimental results are rationalized terms interaction...
The Ethiopia and Zaire events exhibit normal faulting as would be expected for their rift zone locations. 1968 May 15 Zambia event is unusual in that P-pP separation times place its focus the lower crust (28 km) which may below brittle/ductile transition implying high strain rates. Inversion yielded a angle fault. depth focal mechanism of this event, along with December 2 suggest southwestward extension. Teleseismic long period vertical P-waves from South Africa distortions attributed to...
It is a matter of current debate whether the gate-tunable superconductivity in twisted bilayer graphene phonon mediated or arises from electron-electron interactions. The recent observation strong coupling electrons to so-called $K$-phonon modes angle-resolved photoemission spectroscopy experiments has resuscitated early proposals that $K$ phonons drive superconductivity. We show bandwidth-enhancing effect interactions drastically weakens both intrinsic susceptibility towards pairing as well...