Off-resonance magnetoresistance spike in irradiated ultraclean 2D electron systems

Jesus Iñarrea

doi:10.1186/1556-276x-8-241

Abstract

We report on the theoretical studies of a recently discovered strong radiation-induced magnetoresistance spike obtained in ultraclean two-dimensional electron systems at low temperatures. The most striking feature of this spike is that it shows up on the second harmonic of the cyclotron resonance. We apply the radiation-driven electron orbits model in the ultraclean scenario. Accordingly, we calculate the new average advanced distance by the electron in a scattering event which will define the unexpected resonance spike position. Calculated results are in good agreement with experiments.

Highlights

Transport excited by radiation in a two-dimensional electron system (2DES) has been always [1,2,3] a central topic in basic and especially in applied research
It was discovered that when a high mobility 2DES in a low and perpendicular magnetic field (B) is irradiated, mainly with microwaves (MW), some striking effects are revealed: radiation-induced magnetoresistance (Rxx) oscillations and zero resistance states (ZRS) [4,5]
The only different feature in these experiments [19] is the use of ultraclean samples with mobility μ ∼ 3×107 cm2 V s−1 and lower temperatures T ∼ 0.4 K

Summary

Background

Transport excited by radiation in a two-dimensional electron system (2DES) has been always [1,2,3] a central topic in basic and especially in applied research. An interesting and challenging experimental results, recently obtained [19] and as intriguing as ZRS, consists in a strong resistance spike which shows up far off-resonance. It occurs at twice the cyclotron frequency, w ≈ 2wc [19], where w is the radiation frequency, and wc is the cyclotron frequency. For the previous ‘standard’ experiments and samples [4,5], mobility is lower (μ < 107 cm V s−1) and T higher (T ≥ 1.0 K) We extend this model to an ultraclean sample, where the Landau levels (LL), which in principle are broadened by scattering, become very narrow. The cyclotron resonance is apparently shifted to a new B-position around w ≈ 2wc

Methods

Results and discussion

Conclusions