Microwave-induced zero-resistance states are not necessarily static

Abstract

We study the eect of inhomogeneities in Hall conductivity on the nature of the Zero Resistance States seen in the microwave irradiated two-dimensional electron systems in weak perpendicular magnetic elds, and we show that time-dependent domain patterns may emerge in some situations.For an annular Corbino geometry, with an equilibrium charge density that varies linearly with radius, we nd a time-periodic non-equilibrium solution, which might be detected by a charge sensor, such as an SET. For a model on a torus, in addition to static domain patterns seen at high and low values of the equilibrium charge inhomogeneity, we nd that, in the intermediate regime, a variety of nonstationary states can also exist. We catalog the possibilities we have seen in our simulations. Within a particular phenomenological model, we show that linearizing the nonlinear charge continuity equation about a particularly simple domain wall conguration and analyzing the eigenmodes allows us to estimate the periods of the solutions to the full nonlinear equation.

Nonequilibrium phenomena in high Landau levels

“…They obtained σ = Cσ 1 ( |E dis | )/E c , with a numerical prefactor C ∼ 1 depending on the specific form (or statistics) of the potential. Finkler and Halperin (2009) found that even in a homogeneous system creating additional domains may be favorable. They pointed out that the Lyapunov "energy" ǫ dw of the domain wall depends on the angle φ between the wall and the field in the domains.…”

“…They conjecture that a more realistic Lyapunov function might yield a smaller value of this ratio, thus favoring additional domains. Finkler and Halperin (2009) consider further the effect of spatial variation of the Hall conductivity σ H and show that in this situation non-stationary (periodic) solutions may emerge. The simplest example is the Corbino geometry with Hall conductivity changing linearly along the y axis (radial coordinate), dσ H /dy = α.…”

Effect of rotation of the polarization of linearly polarized microwaves on the radiation-induced magnetoresistance oscillations

“…[2] In the recent past, low-B transport studies under microwave irradiation in the 2DES uncovered the possibility of eliminating backscattering by photo-excitation, without concurrent Hall quantization. [3,4] The experimental realization of such radiation-induced zero-resistance states, and associated B −1 -periodic radiation-induced magnetoresistance oscillations expanded the experimental [3][4][5][6][7][8][9][10][11][12][13][14][15][17][18][19][20][21] and theoretical [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] investigations of light-matter coupling in low-dimensional electronic systems. Indeed, microwave excitation of semiconductor quantum wells and graphene ribbons is now viewed as an approach to artificially realizing a (Floquet) topological insulator for possible applications in topological quantum computing and spintronics.…”

Microwave-induced electron heating in the regime of radiation-induced magnetoresistance oscillations

“…Periodic in B −1 radiation-induced magnetoresistance oscillations, which lead into the radiation-induced zero-resistance states, are now understood to be a consequence of radiation-frequency (f ), and magnetic field (B) dependent, scattering at impurities [26,28,29] and/or a change in the distribution function, [5,35] while vanishing resistance is thought to be an outcome of negative resistance instability and current domain formation. [27,44] Although there has been much progress in this field, there remain many aspects, such as indications of activated transport, the overlap with quantum Hall effect, and the influence of the scattering lifetimes, that could be better understood from both the experimental and theoretical perspectives.…”