Magnetophotogalvanic Effects Driven by Terahertz Radiation in CdHgTe Crystals with Kane Fermions

Abstract

We report on the observation and comprehensive study of the terahertz radiation induced magneto-photogalvanic effect (MPGE) in bulk CdHgTe crystals hosting Kane fermions. The MPGE has been detected in Cd${}_x$Hg${}_{1-x}$Te films with Cd contents $x=0.15$ and $0.22$ subjected to an in-plane magnetic field. At liquid helium temperature we observed multiple resonances in MPGE current upon variation of magnetic field. In the $x=0.22$ with noninverted band structure, the resonances are caused by cyclotron resonance (CR) and photoionization of an impurity level. In the $x=0.15$ films with an inverted band structure, they originate from the CR and interband optical transitions. Band structure calculated by the Kane model perfectly describes positions of all resonances. In particularly, the resonant MPGE caused by interband transitions excited by THz radiation is caused by the gapless energy spectrum of Kane fermions realized in materials with certain Cd contents and temperature range. In addition to the resonant MPGE current we detected a nonresonant one due to indirect optical transitions (Drude-like). This contribution has a nonmonotonic magnetic field dependence increasing linearly at low magnetic field $B$, approaching a maximum at moderate field and decreasing at high $B$. While the nonresonant MPGE decreases drastically with increasing temperature, it is well measurable up to room temperature. The developed theory demonstrates that the MPGE current arises due to cubic in momentum spin-dependent terms in the scattering probability. The asymmetry caused by these effects results in a pure spin current which is converted into an electric current due to the Zeeman effect.

References in corpus (21)

• 3D massless Kane fermions observed in a zinc-blende crystal
• Microwave-induced magnetotransport phenomena in two-dimensional electron systems: Importance of electrodynamic effects
• Magneto-optical signature of massless Kane electrons in Cd3As2
• Temperature-driven massless Kane fermions in HgCdTe crystals: verification of universal velocity and rest-mass description
• Superradiant Decay of Cyclotron Resonance of Two-Dimensional Electron Gases
• Transport properties of a 3D topological insulator based on a strained high mobility HgTe film
• Magneto-gyrotropic effects in semiconductor quantum wells (review)
• Zero-bias spin separation
• Magneto-Gyrotropic Photogalvanic Effects in Semiconductor Quantum Wells
• Pressure and temperature driven phase transitions in HgTe quantum wells
• Giant spin-polarized current in a Dirac fermion system at cyclotron resonance
• Observation of Volkov-Pankratov states in topological HgTe heterojunctions using high-frequency compressibility
• Suppressed Auger scattering and tunable light emission of Landau-quantized massless Kane electrons
• Quantum Oscillations of Photocurrents in HgTe Quantum Wells with Dirac and Parabolic Dispersions
• Symmetry breaking and circular photogalvanic effect in epitaxial Cd${}_x$Hg${}_{1-x}$Te films
• Terahertz Magnetospectroscopy of Cyclotron Resonances from Topological Surface States in Thick Films of Cd${}_x$Hg${}_{1-x}$Te
• Hybridization of topological surface states with a flat band
• Disorder-induced topological phase transition in HgCdTe crystals
• Transport properties of a 1000-nm HgTe film: the interplay of surface and bulk carriers
• Roles of band gap and Kane electronic dispersion in the THz-frequency nonlinear optical response in HgCdTe
• Weak antilocalization in partially relaxed 200-nm HgTe films

Cited by in corpus (3)

• Bleaching of the Terahertz Magneto-Photogalvanic Effect in CdHgTe Crystals with Kane Fermions
• Limiting performance of graphene bilayer sub-terahertz detectors at large induced band gap
• Positive Terahertz Photoconductivity in CdHgTe Under Hydrostatic Pressure