Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Topological Insulators (joint session TT/MA)
TT 3.1: Vortrag
Montag, 1. April 2019, 09:30–09:45, Theater
Coexistence of trivial and topological edge states in two-dimensional topological insulators — T. L. van den Berg1,2, M. R. Calvo3,4, and •D. Bercioux1,4 — 1Donostia International Physics Center, Paseo Manuel de Lardizbal 4, E-20018 San Sebastián, Spain — 2Centro de Física de Materiales (CFM-MPC) Centro Mixto CSIC-UPV/EHU,E-20018 Donostia-San Sebastián, Spain — 3CIC nanoGUNE, 20018 Donostia – San Sebastián, Spain — 4IKERBASQUE, Basque Foundation of Science, 48011 Bilbao, Spain
In this work, we show how the coexistence of trivial and topological edge states for the case of two-dimensional topological insulators (2DTIs) can occur in two different scenarios. In one case, we consider a space modulation of the gap parameter from topological to trivial. This scenario results in the so-called Volkov-Pankratov states (VPSs) [1]. In a second case, we consider the modulation of the chemical potential in an inverted gap 2DTI, similar to the traditional band pinning of semiconductors [2]. Also within this method, we obtain trivial edge states similar to the VPSs. In both cases, the trivial states lead to an enhancement of the edge conductance over the nominal maximum values
of 2e2/h expected in the presence of topological edge states.
We propose several experiments that could demonstrate the presence of such trivial states in 2DTIs.
[1] B.A. Volkov & O.A. Pankratov, JETP Lett. 42, 178 (1985).
[2] R. T. Tung, Appl. Phys. Rev. 1, 011304 (2014).