Bleaching of the Terahertz Magneto-Photogalvanic Effect in CdHgTe Crystals with Kane Fermions

Abstract

We report the observation and comprehensive study of the complex nonlinear intensity dependence of the magneto-photogalvanic effect (MPGE) current induced by terahertz (THz) radiation in Cd${}_x$Hg${}_{1-x}$Te films with inverted ($x=0.15$) and noninverted ($x=0.22$) band structures. The nonlinearities are studied for the resonant MPGE caused by cyclotron resonance, interband transitions between Landau levels, and ionization impurities, as well as for nonresonant indirect Drude-like optical transitions. We show that all these processes lead to the saturation of the photocurrent caused by absorption bleaching. We develop a theoretical framework for each mechanism, which describes measured nonlinearities over an intensity range from 10${}^{-3}$ to $4\times 10^4$ W/cm${}^2$. Furthermore, we demonstrate that the saturation processes for these absorption channels differ significantly, allowing us to analyze them independently by considering different intensity regimes. The observed nonlinearities enable us to determine the energy relaxation times of Kane fermions excited by CR and interband optical transitions.

arXiv comment9+2 pages, 6 figures

References in corpus (13)

• 3D massless Kane fermions observed in a zinc-blende crystal
• Cyclotron resonance harmonics in the ac response of a 2D electron gas with smooth disorder
• Magneto-optics of massless Kane fermions: Role of the flat band and unusual Berry phase
• Temperature-driven massless Kane fermions in HgCdTe crystals: verification of universal velocity and rest-mass description
• Magneto-gyrotropic effects in semiconductor quantum wells (review)
• Temperature-driven single-valley Dirac fermions in HgTe quantum wells
• Suppressed Auger scattering and tunable light emission of Landau-quantized massless Kane electrons
• Linear photogalvanic effect in surface states of topological insulators
• High frequency impact ionization and nonlinearity of photocurrent induced by intense terahertz radiation in HgTe-based quantum well structures
• Nonlinear optical absorption and photocurrents in topological insulators
• Terahertz Magnetospectroscopy of Cyclotron Resonances from Topological Surface States in Thick Films of Cd${}_x$Hg${}_{1-x}$Te
• Disorder-induced topological phase transition in HgCdTe crystals
• Magnetophotogalvanic Effects Driven by Terahertz Radiation in CdHgTe Crystals with Kane Fermions

Cited by in corpus (2)

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• Positive Terahertz Photoconductivity in CdHgTe Under Hydrostatic Pressure