Low Temperature Physics: 35, 6 (2009); https://doi.org/10.1063/1.3064862 (9 pages)
Two-dimensional electron systems in HgTe quantum wells
Z.D. Kvon1,2, E.B. Olshanetsky1, N.N. Mikhailov1, and D.A. Kozlov1
1Institute of Semiconductor Physics, Novosibirsk 630090, Russia
2Novosibirsk state university, street. Pirogova, 2, Novosibirsk, 630090, Russia
Received Jule 7, 2008
This publication gives a short review of the properties of two-dimensional electron systems in quantum wells based on a double heterostructure CdHgTe/HgTe/CdHgTe with surface orientations (100) and (013). The main features of the electron system energy spectrum are described. The dependence of the effective mass of two-dimensional electrons in HgTe quantum wells versus their density (2,2·1011 cм-2≤Ns≤ 9,6·1011 cм-2) has been obtained from the cyclotron resonance measurements. This dependence is indicative of a marked nonparabolicity of the energy spectrum: the effective mass increases with the density Ns from (0.026±0.005)m0 to (0.0335±0.005)m0. The paper contains a discussion of a giant spin splitting observed in asymmetrical HgTe quantum wells and presents the results of the experimental study of the quantum Hall liquid–quantum Hall insulator and plateau–plateau transitions in a two-dimensional electron system in HgTe quantum wells. Also presented in the paper is a new type of electron-hole system observed in the investigated HgTe quantum wells that is the first realization of a two-dimensional semimetal. It is established that this system is realized in weakly doped quantum wells with inverted band structure and surface orientation (013). A number of magnetotransport phenomena associated with a co-existence of two-dimensional electrons and holes has been observed: a positive magnetoresistance, a variable-sign Hall effect, an anomalous behavior in the quantum Hall effect regime.
PACS: 73.43.Qt Magnetoresistance;
Key words: electrons and holes, semimetals, gapless semiconductos, quantum wells.