Cyclotron resonance in HgTe/CdTe-based heterostructures in high magnetic fields

Maxim S Zholudev,Anton V Ikonnikov,Kirill E Spirin,Frederic Teppe,Nikolay N Mihailov,Milan Orlita,Vladimir I Gavrilenko,Sergey A Dvoretskiy,Wojciech Knap,Kirill V Maremyanin

doi:10.1186/1556-276x-7-534

Abstract

Cyclotron resonance study of HgTe/CdTe-based quantum wells with both inverted and normal band structures in quantizing magnetic fields was performed. In semimetallic HgTe quantum wells with inverted band structure, a hole cyclotron resonance line was observed for the first time. In the samples with normal band structure, interband transitions were observed with wide line width due to quantum well width fluctuations. In all samples, impurity-related magnetoabsorption lines were revealed. The obtained results were interpreted within the Kane 8·8 model, the valence band offset of CdTe and HgTe, and the Kane parameter EP being adjusted.

Highlights

HgTe/CdTe-based quantum wells (QWs) exhibit a number of remarkable properties
At the critical HgTe QW thickness (6.3 to 7 nm depending on Cd content in the barrier), the forbidden gap is absent and both electrons and holes are characterized by the linear energy-momentum law of massless Dirac fermions [1,2]
We present the first results on cyclotron resonance (CR) measurements in a semimetallic sample with wide HgTe QW as well as in two samples with normal band structures: narrow HgTe QW and wide HgCdTe

Summary

Introduction

HgTe/CdTe-based quantum wells (QWs) exhibit a number of remarkable properties. At the critical HgTe QW thickness (6.3 to 7 nm depending on Cd content in the barrier), the forbidden gap is absent and both electrons and holes are characterized by the linear energy-momentum law of massless Dirac fermions [1,2]. In the inverted band structure regime, HgTe QWs are shown to be two-dimensional (2D) topological insulators that have attracted a great fundamental interest [1,2,4,5] It was demonstrated [4] that a quantum spin Hall insulator state exists in such systems that can be destroyed by magnetic field due to crossing of Landau levels of different bands [6]. These two levels have recently shown to display the effect of the avoided crossing [7,8].

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Conclusion