Photoconductivity in AC-driven modulated two dimensional electron gas in a perpendicular magnetic field

Abstract

In this work we study the microwave photoconductivity of a two-dimensional electron system (2DES) in the presence of a magnetic field and a two-dimensional modulation (2D). The model includes the microwave and Landau contributions in a non-perturbative exact way, the periodic potential is treated perturbatively. The Landau-Floquet states provide a convenient base with respect to which the lattice potential becomes time-dependent, inducing transitions between the Landau-Floquet levels. Based on this formalism, we provide a Kubo-like formula that takes into account the oscillatory Floquet structure of the problem. The total longitudinal conductivity and resistivity exhibit strong oscillations, determined by $\epsilon =\omega /{\omega }_c$ with $\omega$ the radiation frequency and ${\omega }_c$ the cyclotron frequency. The oscillations follow a pattern with minima centered at $\omega /{\omega }_c=j+1/2(l-1)+\delta$, and maxima centered at $\omega /{\omega }_c=j+1/2(l-1)-\delta$, where $j=1,2,\mathrm{3.......}$, $\delta \sim 1/5$ is a constant shift and $l$ is the dominant multipole contribution. Negative resistance states (NRS) develop as the electron mobility and the intensity of the microwave power are increased. These NRS appear in a narrow window region of values of the lattice parameter ($a$), around $a\sim l_B$, where $l_B$ is the magnetic length. It is proposed that these phenomena may be observed in artificially fabricated arrays of periodic scatterers at the interface of ultraclean $GaAs/A{l}_{x}G{a}_{1-x}As$ heterostructures.

20 pages, 8 figures

References in corpus (3)

• Theory of microwave-induced oscillations in the magnetoconductivity of a 2D electron gas
• Radiation-Induced "Zero-Resistance State" and the Photon Assisted Transport
• Surface acoustic wave induced magnetoresistance oscillations in a 2D electron gas

Cited by in corpus (10)

• Mechanisms of the microwave photoconductivity in 2D electron systems with mixed disorder
• Microwave photoconductivity of a 2D electron gas: Mechanisms and their interplay at high radiation power
• Magnetoresistance Oscillations in Two-dimensional Electron Systems Induced by AC and DC Fields
• Microwave photoresistance of a high-mobility two-dimensional electron gas in a triangular antidot lattice
• Nonlinear Current of Strongly Irradiated Quantum Hall Gas
• Driving Weiss oscillations to Zero Resistance States by Microwave Radiation
• Theory of the microwave-induced photocurrent and photovoltage magnetooscillations in a spatially non-uniform 2D electron gas
• Nonlinear theory of fractional microwave-induced magnetoresistance oscillations in a dc-driven two-dimensional electron system
• Nonlinear magnetoresistance of an irradiated two-dimensional electron system
• Hall field induced magnetoresistance oscillations of a two-dimensional electron system