Terahertz imaging of Landau levels in HgTe-based topological insulators

Journal Article · Mon Jun 27 00:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4955018· OSTI ID:22590655

Kadykov, Aleksandr M.; Krishtopenko, Sergey S. ^[1]; Torres, Jeremie ^[2]; Consejo, Christophe; Ruffenach, Sandra; Marcinkiewicz, Michal; But, Dmytro; Teppe, Frederic ^[1]; Knap, Wojciech ^[1]; Morozov, Sergey V.; Gavrilenko, Vladimir I. ^[3]; Mikhailov, Nikolai N. ^[4]; Dvoretsky, Sergey A. ^[4]

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1. Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS–Université de Montpellier, Montpellier (France)
2. Institut d'Electronique et des Systèmes (IES), UMR 5214 CNRS–Université de Montpellier, Montpellier (France)
3. Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation)
4. Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent'eva 13, 630090 Novosibirsk (Russian Federation)

We report on sub-terahertz photoconductivity under the magnetic field of a two dimensional topological insulator based on HgTe quantum wells. We perform a detailed visualization of Landau levels by means of photoconductivity measured at different gate voltages. This technique allows one to determine a critical magnetic field, corresponding to topological phase transition from inverted to normal band structure, even in almost gapless samples. The comparison with realistic calculations of Landau levels reveals a smaller role of bulk inversion asymmetry in HgTe quantum wells than it was assumed previously.

• OSTI ID: 22590655
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 26 Vol. 108; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
ELECTRIC POTENTIAL
MAGNETIC FIELDS
MERCURY TELLURIDES
PHASE TRANSFORMATIONS
PHOTOCONDUCTIVITY
QUANTUM WELLS
TOPOLOGY
TWO-DIMENSIONAL SYSTEMS