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We analyze a phase-sensitive contribution to the oscillating magnetoresistance induced by the combined driving of two microwave fields having commensurate frequencies ω1 and ω2 (m1ω1+m2ω2=0 for at least a set of nonzero integers m1 and m2), based on the balance-equation approach to magnetotransport for high-density two-dimensional electron systems. This commensurate oscillating photoresistance not only depends on the frequencies and polarizations of both microwaves, but varies drastically when changing the relative phases of two incident radiation fields. It shows up most significantly in the case of ω2/ω1=3 and may lead to a phase-controllable change of more than a factor of two in the total magnetoresistivity in the vicinity of ω1/ωc=1.5 and 2.5 (ωc is the cyclotron frequency), when both radiation fields are linearly x-direction polarized. [ABSTRACT FROM AUTHOR]

A momentum balance equation is developed to investigate the magnetotransport properties in monolayer molybdenum disulphide when a strong perpendicular magnetic field and a weak in-plane electric field are applied simultaneously. At low temperature, in the presence of intravalley impurity scattering, Shubnikov–de Haas oscillation shows up accompanied by a beating pattern arising from large spin splitting and its period may halve due to the high-order oscillating term at large magnetic field for samples with ultrahigh mobility. In the case of intervalley disorders, there exists a magnetic-field range where the magnetoresistivity almost vanishes. For a low-mobility layer, a phase inversion of oscillating peaks is acquired in accordance with recent experiment. At high temperature when Shubnikov–de Haas oscillation is suppressed, the magnetophonon resonances induced by both optical phonons (mainly due to homopolar and Frohlich modes) and acoustic phonons (mainly due to intravalley transverse and longitudinal acoustic modes) emerge for a suspended system with high mobility. For the single layer on a substrate, another resonance due to surface optical phonons may occur, resulting in a complex behavior of the total magnetoresistance. The beating pattern of magnetophonon resonance due to optical phonons can also be observed. However, for a nonsuspended layer with low mobility, the magnetoresistance oscillation almost disappears and the resistivity increases with field monotonically. [ABSTRACT FROM AUTHOR]

We examine the effect of changing the linear polarization angle θ of incident microwaves with respect to the dc current on radiation-induced magnetoresistance oscillations in a two-dimensional (2D) system within the balance-equation formulation of the photon-assisted magnetotransport model, considering the radiative decay as the sole damping mechanism. At an extremum the amplitude of oscillatory magnetoresistance Rxx exhibits a sinusoidal, up to a factor of 5, magnitude variation with rotating the polarization angle θ. The maximal amplitude shows up generally at a nonzero θ, which is dependent upon the extremum in question, the 2D electron setup, the radiation frequency, and the magnetic field orientation. These results provide a natural explanation for the experimental observations by Mani et al. [ Phys. Rev. B 84 085308 (2011)] and Ramanayaka et al. [ Phys. Rev. B 85 205315 (2012)]. [ABSTRACT FROM AUTHOR]

Microwave-induced magnetoresistance oscillations in two-dimensional electron systems are examined from a photon-assisted transport scheme with short-range impurity scatterings. Analytical results at high filling factors strongly support early considerations and the recent experimental observation that the temperature dependence of the oscillation amplitude is exponential and originates primarily from the single-particle lifetime. [ABSTRACT FROM AUTHOR]

Nonlinear magnetotransport of a microwave-irradiated high-mobility two-dimensional electron system under a finite direct current excitation is analyzed using a dc-controlled scheme with photon-assisted transition mechanism. The predicted amplitudes, extrema, and nodes of the oscillatory differential resistance versus the magnetic field and the current density are in excellent agreement with the recent experimental observation [Hatke et al. Phys. Rev. B 77, 201304(R) (2008)]. [ABSTRACT FROM AUTHOR]

Magnetoresistance oscillations in two-dimensional electron systems driven simultaneously by a strong direct current and a microwave irradiation are analyzed within a unified microscopic scheme treating both excitations on an equal footing. The microwave-induced resistance oscillations are described by a parameter εω proportional to the radiation frequency, while the dc-induced resistance oscillations are governed by a parameter εj proportional to the current density. In the presence of both a microwave radiation and a strong dc, the combined parameter εω+εj is shown to control the main resistance oscillations, in agreement with the recent measurement [Zhang et al., Phys. Rev. Lett. 98, 106804 (2007)]. [ABSTRACT FROM AUTHOR]

Electric current-induced magnetoresistance oscillations recently discovered in two-dimensional electron systems are analyzed using a microscopic scheme for nonlinear magnetotransport direct controlled by the current. The magnetoresistance oscillations are shown to result from drift-motion assisted electron scatterings between Landau levels. The theoretical predictions not only reproduce all the main features observed in the experiments but also disclose other details of the phenomenon. [ABSTRACT FROM AUTHOR]

The magnetoresistance oscillations in high-mobility two-dimensional electron systems induced by two radiation fields of frequencies 31 and 47 GHz are analyzed in a wide magnetic-field range down to 100 G, using the balance-equation approach to magnetotransport for high-carrier-density systems. The frequency mixing processes are shown to be important. The predicted peak positions, relative heights, radiation-intensity dependence and their relation with monochromatic resistivities are in good agreement with recent experimental finding [M. A. Zudov et al., Phys. Rev. Lett. 96, 236804 (2006)]. [ABSTRACT FROM AUTHOR]

Recently discovered modulations of Shubnikov–de Haas oscillations in microwave-irradiated two-dimensional electron systems are shown to arise from electron heating induced by the radiation. The electron temperature, obtained by balancing the energy absorption from the microwave field and the energy dissipation to the lattice through realistic electron-phonon couplings, exhibits resonance. The modulation of the Shubnikov–de Haas oscillation and the suppression of magnetoresistance are demonstrated together with microwave-induced resistance oscillation, in agreement with experimental findings. [ABSTRACT FROM AUTHOR]

Far infrared photoresponse of magnetoresistivity ΔR[sub xx] of two-dimensional electron systems is investigated theoretically at high temperatures. Photon-assisted impurity and phonon scatterings, rather than the electron heating, are shown to be the dominant mechanisms for high-temperature photoresponse at cyclotron resonance. Based on the theory developed for electron magnetotransport driven by intense terahertz radiations, we have calculated the far infrared photoresistivity of a GaAs/AlGaAs heterostructure at temperature T=150 K, predicting notable cyclotron resonance of ΔR[sub xx], in agreement with the experimental finding. Contrary to low temperature case, where the electron heating is almost solely responsible for the cyclotron resonance of ΔR[sub xx], at T=150 K electron-heating contribute at most a small fraction of the total response. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]