Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg1-x Cd x Te

Alexandra V Galeeva; Alexey I Artamkin; Alexey S Kazakov; Sergey N Danilov; Sergey A Dvoretskiy; Nikolay N Mikhailov; Ludmila I Ryabova; Dmitry R Khokhlov

doi:10.3762/bjnano.9.96

Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg_1-_x Cd _x Te

Beilstein J Nanotechnol. 2018 Mar 29:9:1035-1039. doi: 10.3762/bjnano.9.96. eCollection 2018.

Authors

Alexandra V Galeeva¹, Alexey I Artamkin¹, Alexey S Kazakov¹, Sergey N Danilov², Sergey A Dvoretskiy³, Nikolay N Mikhailov³, Ludmila I Ryabova⁴, Dmitry R Khokhlov^{1

5}

Affiliations

¹ Physics Department, M.V. Lomonosov Moscow State University, Leninskie Gory 1 bld.2, 119991 Moscow, Russia.
² Faculty of Physics, University of Regensburg, Universitaetstr. 31, D-93053 Regensburg, Germany.
³ Rzhanov Institute of Semiconductor Physics, pr. Lavrentieva 13, 630090 Novosibirsk, Russia.
⁴ Chemistry Department, M.V. Lomonosov Moscow State University, Leninskie Gory 1 bld.3, 119991 Moscow, Russia.
⁵ P.N. Lebedev Physical Institute, Leninskiy prosp. 53, 119991 Moscow, Russia.

Abstract

Terahertz photoconductivity in heterostructures based on n-type Hg_1-_x Cd _x Te epitaxial films both in the topological phase (x < 0.16, inverted band structure, zero band gap) and the trivial state (x > 0.16, normal band structure) has been studied. We show that both the positive photoresponse in films with x < 0.16 and the negative photoconductivity in samples with x > 0.16 have no low-energy threshold. The observed non-threshold positive photoconductivity is discussed in terms of a qualitative model that takes into account a 3D potential well and 2D topological Dirac states coexisting in a smooth topological heterojunction.

Keywords: photoconductivity; terahertz radiation; topological insulator.