Absolute negative conductivity in two-dimensional electron systems associated with acoustic scattering stimulated by microwave radiation

Abstract

We discuss the feasibility of absolute negative conductivity (ANC) in two-dimensional electron systems (2DES) stimulated by microwave radiation in transverse magnetic field. The mechanism of ANC under consideration is associated with the electron scattering on acoustic piezoelectric phonons accompanied by the absorption of microwave photons. It is demonstrated that the dissipative components of the 2DES dc conductivity can be negative (σxx = σyy < 0) when the microwave frequency Ω is somewhat higher than the electron cyclotron frequency Ωc or its harmonics. The concept of ANC associated with such a scattering mechanism can be invoked to explain the nature of the occurrence of zero-resistance "dissipationless" states observed in recent experiments.

Circular-Polarization-Dependent Study of the Microwave Photoconductivity in a Two-Dimensional Electron System

“…First some mechanism produces an oscillatory photoconductivity contribution that may turn the overall dissipative conductivity negative near the minima. Examples of proposed mechanisms include spatially indirect interLandau-level transitions based on impurity and phonon scattering [11,12,13,14,15,16,17,18,19], the establishement of a non-equilibrium distribution function [3,20,21,22], photon assisted quantum tunneling [23] and non-parabolicity effects [24]. Second, it is argued that negative values of the dissipative conductivity render the initially homogeneous system unstable [25,26] and an inhomogeneous domain structure develops instead [26,27,28,29,30], which results in zero resistance in experiment.…”

Calculation of the nonlinear free-carrier absorption of terahertz radiation in semiconductor heterostructures

“…To calculate the absorption of the THz radiation, electrical current in the absence of any probing field must be calculated. Such a current cannot be obtained from the previous theory [12][13][14][15][16] because the current obtained there vanishes when the probing field is removed. Furthermore, in the limit of zero radiation field, all existing theories predicted a quadratic dependence of the current on the radiation field while the experiment 11 clearly shows a linear dependence.…”

“…[1][2][3][4][5][6][7][8] The discovery of a new magnetoresistance oscillation and zero-resistance state in high-mobility electronic systems [9][10][11] has stimulated new theoretical interest in the transport properties of electrons under electromagnetic radiation. [12][13][14][15] A satisfactory understanding of the observed dc magnetoresistance oscillation has been achieved. 12,14,15 There are three different theoretical methods of calculating the electrical transport under a radiation.…”

Magnetoresistivity modulated response in bichromatic microwave irradiated two dimensional electron systems

“…This modulation results to be tunable by increasing intensity of one of the MW sources keeping the other constant. All these experimental evidences establish real challenges for the theoretical models presented to date 12,13,14,15,16,17,18,19,20 . Considering that all these models are not able to achieve consensus about the true origin of these striking phenomena, the new experimental results can be regarded as crucial tests for theories, for the existing ones, and for the ones to come.…”