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TT: Fachverband Tiefe Temperaturen

TT 20: Topological Semimetals II

TT 20.10: Talk

Monday, March 12, 2018, 17:30–17:45, A 053

Creating and Controlling Dirac Fermions, Weyl Fermions, and Nodal Lines in the Magnetic Antiperovskite Eu₃PbO — •Moritz M. Hirschmann¹, Alexandra S. Gibbs², Vahideh Abdolazimi¹, Alexander Yaresko¹, Hidenori Takagi^1,3,4, Andreas W. Rost^1,3, and Andreas P. Schnyder¹ — ¹Max Planck Institute for Solid State Research, Stuttgart, Germany — ²ISIS Pulsed Neutron Facility, Didcot, United Kingdom — ³FMQ, Universität Stuttgart, Germany — ⁴Department of Physics, The University of Tokyo, Japan

Anti-perovskite materials A₃EO, where A denotes an alkaline earth metal, while E stands for Pb or Sn, exhibit low-energy electronic properties that are described by three-dimensional Dirac fermions, which are gapped out by spin-orbit coupling [1,2]. If A is replaced by the rare-earth element europium then magnetic order is expected due to the electron spin moment as confirmed by magnetization measurements. Neutron diffraction leads us to the conclusion that different magnetic phases appear. We studied the effect of magnetism on the electronic properties of Eu₃PbO. From DFT calculations the resulting splitting has been extracted and implemented into a tight-binding model to capture the physics close to the Fermi energy. We present the creation of Weyl points and nodal lines and give their topological invariants. For the different magnetic phases we derived the respective surface states and anomalous Hall responses.

[1] T. H. Hsieh, J. Liu, L. Fu. Phys. Rev. B, 90 (2014) 08111.

[2] D. Samal, H. Nakamura, H. Takagi. APL Mater. 4 (7), 2016.