Readspeaker Menü

Banner Bild

Veranstaltungskalender

Prof. Dr. Claudia Felser, Max-Planck Institute for Chemical Physics and Solids, Dresden
Weyl Semimetals and beyond!
Veranstaltungsart: Physikalisches Kolloquium
Zeit: 15.01.2018, 16:15 - 17:30 Uhr
Ort: Hörsaal 1, Abbeanum
Veranstalter: Physikalisch-Astronomische Fakultät
Ansprechpartner:

Dekanat

Max-Wien-Platz 1

07743 Jena

Tel. 03641 9-47001

Details:

 

Topology a mathematical concept became recently a hot topic in condensed matter physics and materials science. Classically, we know insulators, semimetals and metals, determined by their band gaps and electronic structure. However, all known materials can be reclassified through the lens of topology. Topological insulators, Weyl and Dirac Semimetals and topological metals are a new quantum state of matter, which have attracted interest of condensed matter science and materials science. One important criteria for the identification of the topological material is in the language of chemistry the inert pair effect of the s-electrons in heavy elements and the symmetry of the crystal structure [1]. Beside of Weyl and Dirac new fermions can be identified compounds via linear and quadratic 3-, 6- and 8- band crossings stabilized by space group symmetries [2]. Unusual electronic properties can be found also in these compounds. 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. [3-7]. In NbP nano wires we have observed the chiral anomaly [8]. NbP has served as a model system for the gravitational anomaly in astrophysics [9] and WP2 for a hydrodynamic flow of electrons [10]. MoP and WP2 show exceptional properties such as high conductivity (higher than copper), high mobilties and a high magneto-resistance effect.  With thermal and magnetoelectric transport experiments, a transition from a hydrodynamic electron fluid below 15 K into a conventional metallic state at higher temperatures is observed. The hydrodynamic regime is characterized by a viscosity-induced dependence of the electrical resistivity on the square of the channel width that coincides with as strong violation of the Wiedemann-Franz law. Many of these topological materials show unusual Nernst and Seebeck coefficients and a violation of the Wiedemann Franz law [6,7,9-11].

 

 

 

Plan aller Physikalischen Kolloquien im Semester

Termin empfehlen