Terahertz properties of Dirac fermions in HgTe films with optical doping

Abstract

Terahertz properties of mercury telluride (HgTe) films with critical thickness are presented and discussed. The density of the charge carriers is controlled using contact-free optical doping by visible light. In the magneto-optical response of HgTe the contribution of two types of carriers (electrons and holes) can be identified. The density of the electrons can be modified by light illumination by more than one order of magnitude. As the hole density is roughly illuminationindependent, the terahertz response of the illuminated samples becomes purely electronic. In some cases, light illumination may switch the qualitative electrodynamic response from hole-like to the electron-like. The cyclotron mass of the electrons could be extracted from the data and shows a square root dependence upon the charge concentration in the broad range of parameters. This can be interpreted as a clear proof of a linear dispersion relations, i.e. Dirac-type charge carriers.

To be published in "2D Materials"

References in corpus (9)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Field Theory of Time-Reversal Invariant Insulators
• Single valley Dirac fermions in zero-gap HgTe quantum wells
• Giant spin-polarized current in a Dirac fermion system at cyclotron resonance
• Cyclotron resonance photoconductivity of a two-dimensional electron gas in HgTe quantum wells
• Terahertz Quantum Hall Effect in a Topological Insulator
• Quantum Oscillations of Photocurrents in HgTe Quantum Wells with Dirac and Parabolic Dispersions
• Room temperature electrically tunable broadband terahertz Faraday effect

Cited by in corpus (6)

• Band Structure of Two-dimensional Dirac Semimetal from Cyclotron Resonance
• High-frequency breakdown of the integer QHE in GaAs/AlGaAs heterojunctions
• Energy spectrum of semimetallic HgTe quantum wells
• Superradiant and transport lifetimes of the cyclotron resonance in the topological insulator HgTe
• Universal transparency and fine band structure near the Dirac point in HgTe quantum wells
• All-optical band structure reconstruction and onset of Landau quantization of Dirac fermions