Valley Hall transport of photon-dressed quasiparticles in two-dimensional Dirac semiconductors. (7th August 2018)

• Record Type: Journal Article
• Authors: Kovalev, V M; Tse, Wang-Kong; Fistul, M V; Savenko, I G
• Is Part Of: New journal of physics. Volume 20:Number 8(2018:Aug.)
• Publication Date: 2018-08-07
• Subjects: transition-metal dichalcogenides -- valley Hall effect -- photon-dressed quasiparticles -- two-dimensional materials; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aad5f8
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: We present a theory of the photovoltaic valley-dependent Hall effect in a two-dimensional (2D) Dirac semiconductor subject to an intense near-resonant electromagnetic field. Our theory captures and elucidates the influence of both the field-induced resonant interband transitions and the nonequilibrium carrier kinetics on the resulting valley Hall transport in terms of photon-dressed quasiparticles (PDQs). The non-perturbative renormalization effect of the pump field manifests itself in the dynamics of the PDQs, with a quasienergy spectrum characterized by dynamical gaps δ η ( η is the valley index) that strongly depend on field amplitude and polarization. Nonequilibrium carrier distribution functions are determined by the pump field frequency ω as well as the ratio of intraband relaxation time τ and interband recombination time τ rec . We obtain analytic results in three regimes, when (I) all relaxation processes are negligible, (II) τ ≪ τ rec, and (III) τ ≫ τ rec, and display corresponding asymptotic dependences on δ η and ω . We then apply our theory to 2D transition-metal dichalcogenides, and find a strong enhancement of valley-dependent Hall conductivity as the pump field frequency approaches the transition energies between the pair of spin-resolved conduction and valence bands at the two valleys.