Sign-alternating photoconductivity and magnetoresistance oscillations induced by terahertz radiation in HgTe quantum wells

Abstract

We report on the observation of terahertz radiation induced photoconductivity and of terahertz analog of the microwave-induced resistance oscillations (MIRO) in HgTe-based quantum well (QW) structures of different width. The MIRO-like effect has been detected in QWs of 20 nm thickness with inverted band structure and a rather low mobility of about 3 $\times$ 10${}^5$ cm${}^2$/V s. In a number of other structures with QW widths ranging from 5 to 20 nm and lower mobility we observed an unconventional non-oscillatory photoconductivity signal which changes its sign upon magnetic field increase. This effect was observed in structures characterized by both normal and inverted band ordering, as well as in QWs with critical thickness and linear dispersion. In samples having Hall bar and Corbino geometries an increase of the magnetic field resulted in a single and double change of the sign of the photoresponse, respectively. We show that within the bolometric mechanism of the photoresponse these unusual features imply a non-monotonic behavior of the transport scattering rate, which should decrease (increase) with temperature for magnetic fields below (above) the certain value. This behavior is found to be consistent with the results of dark transport measurements of magnetoresistivity at different sample temperatures. Our experiments demonstrate that photoconductivity is a very sensitive probe of the temperature variations of the transport characteristics, even those that are hardly detectable using standard transport measurements.

arXiv comment9 pages, 8 figures

References in corpus (26)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Evidence for a New Dissipationless Regime in 2D Electronic Transport
• Single valley Dirac fermions in zero-gap HgTe quantum wells
• Nonequilibrium phenomena in high Landau levels
• Giant microwave photoresistance of two-dimensional electron gas
• Circular polarization dependent study of the microwave photoconductivity in a two-dimensional electron system
• Demonstration of a 1/4 cycle phase shift in the radiation-induced oscillatory-magnetoresistance in GaAs/AlGaAs devices
• Observation of Apparently Zero-Conductance States in Corbino Samples
• Giant magnetoresistance oscillations caused by cyclotron resonance harmonics
• Room temperature high frequency transport of Dirac fermions in epitaxially grown Sb_2Te_3 based topological insulators
• Novel Radiation-induced Magnetoresistance Oscillations in a Nondegenerate 2DES on Liquid Helium
• Giant spin-polarized current in a Dirac fermion system at cyclotron resonance
• Classical ratchet effects in heterostructures with a lateral periodic potential
• Cyclotron resonance photoconductivity of a two-dimensional electron gas in HgTe quantum wells
• Photon-induced vanishing of magnetoconductance in 2D electrons on liquid He
• Photogalvanic probing of helical edge channels in 2D HgTe topological insulators
• Spin currents in diluted magnetic semiconductors (extended version)
• Spin relaxation times of 2D holes from spin sensitive bleaching of inter-subband absorption
• Observation of microwave-induced resistance oscillations in strained Ge/SiGe quantum wells
• Circular photogalvanic effect in HgTe/CdHgTe quantum well structures
• Quantum Oscillations of Photocurrents in HgTe Quantum Wells with Dirac and Parabolic Dispersions
• Photo-Conductivity Response at Cyclotron-Resonance Harmonics in a Non-Degenerate 2D Electron Gas on Liquid Helium
• Hall field-induced resistance oscillations in Ge/SiGe quantum wells
• Circular-Polarization-Dependent Study of Microwave-Induced Conductivity Oscillations in a Two-Dimensional Electron Gas on Liquid Helium
• Magneto-resistance oscillations induced by high-intensity terahertz radiation
• Spin mixing between subbands and extraordinary Landau levels shift in wide HgTe quantum wells

Cited by in corpus (9)

• Observation of terahertz-induced magnetooscillations in graphene
• Demonstration of high sensitivity of microwave-induced resistance oscillations to circular polarization
• Terahertz photoresistivity of a high-mobility 3D topological insulator based on a strained HgTe film
• Terahertz Magnetospectroscopy of Cyclotron Resonances from Topological Surface States in Thick Films of Cd${}_x$Hg${}_{1-x}$Te
• Observation of High Harmonics of the Cyclotron Resonance in Microwave Transmission of a High-Mobility Two-Dimensional Electron System
• Testing the tomographic Fermi liquid hypothesis with high-order cyclotron resonance
• Circular polarization immunity of the cyclotron resonance photoconductivity in two-dimensional electron systems
• Strongly nonlinear Bernstein modes in graphene reveal plasmon-enhanced near-field magnetoabsorption
• Oscillatory photoresistance on the high field side of the cyclotron resonance