Wydarzenia



Seminarium "Coherence-Correlations-Complexity" (KFT, PWr)

13:15 Wednesday, 10-03-21
Platforma Zoom

Topological effects in SnTe-class multilayers

dr hab. Wojciech Brzezicki

Institute of Physics, Polish Academy of Sciences

The seminar will be broadcast on the Zoom platform (the link will be made available to interested persons after prior contact at ).

Abstract:


We investigate the properties of the low-energy states appearing at atomic steps [1,2] and magneto-transport across the topological transition in the multilayer Sn(Pb)Te(Se) compounds [3]. We calculate the dependence of mirror- and spin-resolved Chern numbers on the number of layers and show that the step states appear when these invariants are different on the two sides of the step. We show that magnetic domain walls support low-energy bound states because the regions with opposite magnetization are topologically distinct, providing a possible explanation for the zero-bias conductance peak observed in the recent experiment [2]. For a similar model we study quantization of the Berry phase along Fermi cross sections due to time-reversal and mirror symmetries to explain magnetoresistance in Pb(Sn)Se. We show by microscopic calculation of the Cooperon propagator that the Hikami-Larkin-Nagaoka formula can be generalized to account for mirror symmetry breaking to explain the emergent length scale present in samples covered by amorphous Se [3].


References:
[1] W. Brzezicki, M. Wysokinski, and T. Hyart, Phys. Rev. B 100, 121107(R) (2019).
[2] G.P. Mazur, K. Dybko, A. Szczerbakow, J. Z. Domagala, A. Kazakov, M. Zgirski, E. Lusakowska, S. Kret, J. Korczak, T. Story, M. Sawicki, and T. Dietl, Phys. Rev. B 100, 041408(R) (2019).
[3] A. Kazakov, W. Brzezicki, T. Hyart, B. Turowski, J. Polaczyński, Z. Adamus, M. Aleszkiewicz, T. Wojciechowski, J.Z. Domagala, O. Caha, A. Varykhalov, G. Springholz, T. Wojtowicz, V.V. Volobuev, and T. Dietl, arXiv:2002.07622.

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