Physikalisches Kolloquium

24.4.2017 16:30, Raum: T-1004
Prof. Dr. Rosario Fazio (Scuola Normale Superiore, Pisa)
Dissipative phase transitions in synthetic matter
24.4.2017 17:30, Raum: T-1004
Prof. Dr. Christoph Strunk (Universität Regensburg)
The superconductor/insulator transition in thin films and wires
15.5.2017 17:15, Raum: T-1004
Prof. Dr. Claudia Felser (Max-Planck-Institut für Chemische Physik fester Stoffe)
Topology – from the materials perspective

Topology – from the materials perspective Claudia FELSER

Max Planck Institute of Chemical Physics for Solids, Dresden, 01187, Germany

Topological insulators, Weyl and Dirac Semimetals are a new quantum state of matter, which have attracted interest of condensed matter science. Tunable families of compounds such as Heusler compounds, binary phosphides and chalcogenides allows for a design of these new properties and their systematic study. Many known compounds were reclassified through the lens of topology.

Heusler compounds are a remarkable class of materials with more than 1,000 members and a wide range of extraordinary multifunctionalities [1] including tunable topological insulators (TI) [2,3] and Weyl semimetals [4,5]. Many of these ternary zero-gap semiconductors in Heusler compounds (LnAuPb, LnPdBi, LnPtSb and LnPtBi) contain the rare-earth element Ln, which can realize additional properties ranging from superconductivity (for example LaPtBi) to magnetism (for example GdPtBi) and heavy fermion behavior (for example YbPtBi). These properties can open new research directions in realizing the quantized anomalous Hall Effect and topological superconductors. C1b Heusler compounds have been grown as single crystals and as thin films. The band inversion is proven by ARPES [6] and a large anomalous Hall can be explained within a Weyl-Berry curvature scenario. Binary phoshides are the ideal material class for a systematic study of Dirac and Weyl physics. Weyl points, a new class of topological phases was also predicted in NbP, NbAs. TaP, MoP and WP2. [7-9]. New Fermions beyond Weyl and Dirac have been predicted by Bernevig’s team and can be classified by space groups and Wyckoff positions [10]. More emerging quantum properties and potential applications will be discussed. Weyl Semimetals NbP TaP and TaAs and the Fermi arc, calculation vs. Angle Resolved Photoemission (ARPES).

[1] Tanja Graf, Stuart S. P. Parkin, and Claudia Felser, Progress in Solid State Chemistry 39 (2011) 1

[2] S. Chadov et al., Nature Materials 9 (2010) 541

[3] H. Lin, et al., Nature Materials 9 (2010) 546

[4] Z. K. Liu, et al., Nature Communication 7 (2016) 12924

[5] M. Hirschberger et al., Nature Materials 15, (2016) 1161

[6] C. Shekhar, et al., preprint: arXiv: 1604.01641

[7] C. Shekhar, et al., Nature Physics 11 (2015) 645

[8] Z. K. Liu, et al., Nature Mat. 15 (2016) 27

[9] L. Yang, et al., Nature Physics 11 (2015) 728

[10] B. Bradlyn, et al., Science 353 (2016) aaf5037

29.5.2017 17:15, Raum: T-1004
Prof. Dr. Reinhold Egger (Universität Düsseldorf)
Towards Quantum Computation with Majorana Fermions
10.7.2017 17:15, Raum: T-1004
Prof. Dr. Ludwig Schultz (Institute of Metallic Materials, IFW Dresden)
Interaction of Ferromagnetic and Superconducting Permanent Magnets: Quantum Levitation or: The Physics Behind the “Back to the Future II” Hoverboard

Die Vorträge finden im Hörsaalzentrum Physik (Gebäude T) statt.

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