Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 51: Topological Semimetals II
TT 51.5: Talk
Wednesday, March 20, 2024, 16:00–16:15, H 3007
Stability of Weyl node merging processes under symmetry constraints — •Viktor Könye1, Gabriele Naselli1, György Frank2, Gergö Pintér2, Dániel Varjas1, János Asbóth2, András Pályi2, and Cosma Fulga1 — 1IFW Dresden, Dresden, Germany — 2Budapest University of Technology and Economics, Budapest, Hungary
Weyl semimetals are topological materials with topologically protected band crossing points called Weyl nodes, characterized by a linear low energy dispersion relation and chirality given by an integer Chern number. By continuously changing the system parameters the number of nodes can only change through charge conserving mergings or creations. When no symmetries are present in the system the most likely process is pairwise annihilation and creation. Pairwise annihilation can be forbidden by adding symmetry constraints and multi-node merging processes can be observed.
Motivated by the prediction of a three-node process in MoTe2 we study merging processes in the presence of C2T symmetry. We find that, when this symmetry is present, the most common merging process involves a three-node process. Additionally we propose a way to realize these merging processes in SrSi2 and in bilayer graphene.
Keywords: Weyl semimetals