Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Georg W. Winkler is active.

Publication


Featured researches published by Georg W. Winkler.


Physical Review X | 2016

Triple Point Topological Metals

Ziming Zhu; Georg W. Winkler; QuanSheng Wu; Ju Li; Alexey A. Soluyanov

Quasiparticles with no direct analogs in the standard model have been recently revealed in experiments. Researchers theoretically analyze the physical properties of triple point fermions, which can be thought of as a melding of Dirac and Weyl fermions.


Physical Review Letters | 2016

Topological Phases in InAs_{1-x}Sb_{x}: From Novel Topological Semimetal to Majorana Wire.

Georg W. Winkler; QuanSheng Wu; Matthias Troyer; Peter Krogstrup; Alexey A. Soluyanov

Superconductor proximitized one-dimensional semiconductor nanowires with strong spin-orbit interaction (SOI) are, at this time, the most promising candidates for the realization of topological quantum information processing. In current experiments the SOI originates predominantly from extrinsic fields, induced by finite size effects and applied gate voltages. The dependence of the topological transition in these devices on microscopic details makes scaling to a large number of devices difficult unless a material with dominant intrinsic bulk SOI is used. Here, we show that wires made of certain ordered alloys InAs_{1-x}Sb_{x} have spin splittings up to 20 times larger than those reached in pristine InSb wires. In particular, we show this for a stable ordered CuPt structure at x=0.5, which has an inverted band ordering and realizes a novel type of a topological semimetal with triple degeneracy points in the bulk spectrum that produce topological surface Fermi arcs. Experimentally achievable strains can either drive this compound into a topological insulator phase or restore the normal band ordering, making the CuPt-ordered InAs_{0.5}Sb_{0.5} a semiconductor with a large intrinsic linear in k bulk spin splitting.


Physical Review Letters | 2017

Orbital Contributions to the Electron g Factor in Semiconductor Nanowires

Georg W. Winkler; Daniel Varjas; Rafal Skolasinski; Alexey A. Soluyanov; Matthias Troyer; Michael Wimmer

Recent experiments on Majorana fermions in semiconductor nanowires [S. M. Albrecht, A. P. Higginbotham, M. Madsen, F. Kuemmeth, T. S. Jespersen, J. Nygård, P. Krogstrup, and C. M. Marcus, Nature (London) 531, 206 (2016)NATUAS0028-083610.1038/nature17162] revealed a surprisingly large electronic Landé g factor, several times larger than the bulk value-contrary to the expectation that confinement reduces the g factor. Here we assess the role of orbital contributions to the electron g factor in nanowires and quantum dots. We show that an L·S coupling in higher subbands leads to an enhancement of the g factor of an order of magnitude or more for small effective mass semiconductors. We validate our theoretical finding with simulations of InAs and InSb, showing that the effect persists even if cylindrical symmetry is broken. A huge anisotropy of the enhanced g factors under magnetic field rotation allows for a straightforward experimental test of this theory.


Physical Review B | 2016

Smooth gauge and Wannier functions for topological band structures in arbitrary dimensions

Georg W. Winkler; Alexey A. Soluyanov; Matthias Troyer

The construction of exponentially localized Wannier functions for a set of bands requires a choice of Bloch-like functions that span the space of the bands in question, and are smooth and periodic functions of


New Journal of Physics | 2017

Hidden Weyl Points in Centrosymmetric Paramagnetic Metals

Dominik Gresch; QuanSheng Wu; Georg W. Winkler; Alexey A. Soluyanov

\mathbf{k}


New Journal of Physics | 2018

Electric field tunable superconductor-semiconductor coupling in Majorana nanowires

Michiel de Moor; Jouri Bommer; Di Xu; Georg W. Winkler; Andrey E. Antipov; Arno Bargerbos; Guanzhong Wang; Nick van Loo; Roy Op het Veld; Sasa Gazibegovic; Diana Car; John Logan; Mihir Pendharkar; Joon Sue Lee; Erik P. A. M. Bakkers; Chris J. Palmstrøm; Roman M. Lutchyn; Leo P. Kouwenhoven; Hao Zhang

in the entire Brillouin zone. For bands with nontrivial topology, such smooth Bloch functions can only be chosen such that they do not respect the symmetries that protect the topology. This symmetry breaking is a necessary, but not sufficient condition for smoothness, and, in general, finding smooth Bloch functions for topological bands is a complicated task. We present a generic technique for finding smooth Bloch functions and constructing exponentially localized Wannier functions in the presence of nontrivial topology, given that the net Chern number of the bands in question vanishes. The technique is verified against known results in the Kane-Mele model. It is then applied to the topological insulator


New Journal of Physics | 2017

Interaction effects in a microscopic quantum wire model with strong spin–orbit interaction

Georg W. Winkler; Martin Ganahl; Dirk Schuricht; Hans Gerd Evertz; Sabine Andergassen

{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}


Proceedings of SPIE | 2016

Topological phases in InAs1−xSbx: from novel topological semimetal to Majorana wire(Conference Presentation)

Georg W. Winkler; QuanSheng Wu; Matthias Troyer; Peter Krogstrup; Alexey A. Soluyanov

, where the topological state is protected by two symmetries: time reversal and inversion. The resultant exponentially localized Wannier functions break both these symmetries. Finally, we illustrate how the calculation of the Chern-Simons orbital magnetoelectric response is facilitated by the proposed smooth gauge construction.


arXiv: Superconductivity | 2018

Topological superconductivity in full shell proximitized nanowires.

Roman M. Lutchyn; Georg W. Winkler; Bernard Van Heck; Torsten Karzig; Karsten Flensberg; Leonid I. Glazman; Chetan Nayak

The transition metal dipnictides TaAs2 , TaSb2 , NbAs2 and NbSb2 have recently sparked interest for exhibiting giant magnetoresistance. While the exact nature of magnetoresistance in these materials is still under active investigation, there are experimental results indicating anisotropic negative magnetoresistance. We study the effect of magnetic field on the band structure topology of these materials by applying a Zeeman splitting. In the absence of magnetic field, we find that the materials are weak topological insulators, which is in agreement with previous studies. When the magnetic field is applied, we find that type-II Weyl points form. This result is found first from a symmetry argument, and then numerically for a k.p model of TaAs2 and a tight-binding model of NbSb2. This effect can be of help in search for an explanation of the anomalous magnetoresistance in these materials.


arXiv: Superconductivity | 2018

A unified numerical approach to semiconductor-superconductor heterostructures.

Georg W. Winkler; Andrey E. Antipov; Bernard Van Heck; Alexey A. Soluyanov; Leonid I. Glazman; Michael Wimmer; Roman M. Lutchyn

We study the effect of external electric fields on superconductor-semiconductor coupling by measuring the electron transport in InSb semiconductor nanowires coupled to an epitaxially grown Al superconductor. We find that the gate voltage induced electric fields can greatly modify the coupling strength, which has consequences for the proximity induced superconducting gap, effective g-factor, and spin-orbit coupling, which all play a key role in understanding Majorana physics. We further show that level repulsion due to spin-orbit coupling in a finite size system can lead to seemingly stable zero bias conductance peaks, which mimic the behavior of Majorana zero modes. Our results improve the understanding of realistic Majorana nanowire systems.

Collaboration


Dive into the Georg W. Winkler's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Michael Wimmer

Vienna University of Technology

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge