Magnetotransport and far‐infrared magneto‐optical studies of molecular‐beam epitaxially grown HgTe

Abstract

A p‐type sample of molecular‐beam epitaxially grown HgTe has been extensively characterized by a series of magnetotransport and far‐infrared magneto‐optical experiments. Hall and resistivity data have been obtained as a function of magnetic field and analyzed by a mixed conduction model. This yields carrier densities and mobilities for the conduction‐band electrons and valence‐band holes as well as additional low‐mobility carriers of both types. Comparison with a detailed transport theory shows that over most of the temperature range between 4.2 and 300 K the electron mobility is dominated by electron–hole scattering. However, the low‐temperature hole mobility is quite sensitive to the ionized impurity concentration, allowing a characterization of the donor and acceptor densities. Analysis of the far‐infrared cyclotron resonance yields the effective mass, density, and mobility of the electrons. By considering the dependence of the low‐temperature intrinsic electron density on magnetic field, the field‐induced band gap has also been evaluated. Impurity‐related magnetoabsorption resonances have been studied, leading to the estimate EA ≊1.2 meV.