Multi-photon structures in the sub-cyclotron-frequency range in microwave photoresistance of a two-dimensional electron system

TL;DR

This paper theoretically investigates how multi-photon processes in microwave photoresistance of a 2D electron system vary with frequency, revealing more pronounced multi-photon structures at lower frequencies that weaken and vanish as frequency increases.

Contribution

It provides a theoretical explanation for the frequency-dependent behavior of multi-photon structures observed in microwave photoresistance experiments.

Findings

More multi-photon structures appear at lower frequencies.

Multi-photon structures weaken and disappear at higher frequencies.

Results agree with recent experimental observations.

Abstract

The frequency dependence of the peak-valley pairs occurring in the magnetoresistivity of a two-dimensional electron system under enhanced microwave irradiation, which are considered to associate with multiphoton processes, is examined in the sub-cyclotron-frequency range, based on a theoretical treatment with photon-assisted electron transitions due to impurity scattering. It is shown that with equivalent radiation power (producing the same height of the main oscillation peak), much more and stronger multi-photon structures show up at lower frequency, and when frequency increases all these structures rapidly weaken, diminish and finally disappear completely. These are in agreement with the recent experimental observation [cond-mat/0608633].