Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 68: Topological Insulators and Weyl Semimetals (joint session MA/TT)
TT 68.10: Vortrag
Mittwoch, 14. März 2018, 17:30–17:45, EB 407
Prediction of a magnetic Weyl semimetal with strong anomalous Hall and Nernst effect in the Heusler compensated ferrimagnet Ti2MnAl — •Jonathan Noky1, Wujun Shi1,2, Lukas Müchler3, Kaustuv Manna1, Yang Zhang1,4, Klaus Köpernik4, Roberto Car3, Jeroen van den Brink4, Claudia Felser1, and Yan Sun1 — 1Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany — 2School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China — 3Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA — 4Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany
We predict the inverse Heusler compound Ti2MnAl, which is a compensated ferrimagnet with a Curie temperature of over 650 K, to be a magnetic Weyl semimetal. Despite the vanishing net magnetic moment, we calculate a large intrinsic anomalous Hall (AHE) and anomalous Nernst (ANE) effect. These effects stem directly from the Berry curvature distribution of the Weyl points, which are only 14 meV away from the Fermi level and isolated from trivial bands. Since spin-rotation symmetry is broken by the magnetic structure, the Weyl points are stable also without spin-orbit coupling. Additionally, because Weyl points of opposite topological charge show a large spatial separation, this system exhibits huge Fermi arcs.
Ti2MnAl and, to a lesser extend, also Ti2MnGa and Ti2MnIn are first examples of systems with Weyl points, large AHE, and large ANE in spite of a vanishing net magnetic moment.