Submillimeter Cyclotron Resonance and Related Phenomena in HgTe

We present the results of far-infrared magnetotransmission experiments on mercury telluride. The experiments are performed on n-type samples in theFaraday and Voigt geometries in the wavelength range from 2 mm to 100 {μ}m at 4.2 K and in magnetic fields up to 58 kG. Both intraband transitions in the Γ₈ conduction band, such as cyclotron resonance, and interband Γ₈→Γ₈ transitions are observed: To analyze the position of the plasma-cylotron-resonance line observed in the Voigt geometry, we discuss the frequency and magnetic field dependence of all the contributions to the dielectric function including that which arises from the interband Γ₈→Γ₈ transitions. The Luttinger parameters γ₁, γ, and κ describing the quantum levels in the Γ₈ bands near the degeneracy point at →k=0 are determined. Absorption lines due to transitions between a discrete acceptor state degenerate with the conduction band and the quantum levels of the conduction band are observed. The activation energy of this acceptor state is found to be EA=0.7±0.1 meV.