Mutual influence between current-induced giant magnetoresistance and radiation-induced magnetoresistance oscillations in the GaAs/AlGaAs 2DES

Abstract

Radiation-induced magnetoresistance oscillations are examined in the GaAs/AlGaAs 2D system in the regime where an observed concurrent giant magnetoresistance is systematically varied with a supplementary dc-current, I dc. The I dc tuned giant magnetoresistance is subsequently separated from the photo-excited oscillatory resistance using a multi-conduction model in order to examine the interplay between the two effects. The results show that the invoked multiconduction model describes the observed giant magnetoresistance effect even in the presence of radiation-induced magnetoresistance oscillations, the magnetoresistance oscillations do not modify the giant magnetoresistance, and the magnetoresistance oscillatory extrema, i.e., maxima and minima, disappear rather asymmetrically with increasing I dc. The results suggest the interpretation that the I dc serves to suppress scattering between states near the Fermi level in a strong magnetic field limit.

Coherent backscattering in quasi-ballistic ultra-high mobility GaAs/AlGaAs 2DES

“…Magnetotransport studies of the ultra high mobility GaAs/AlGaAs 2DES exhibit a small and narrow negative magnetoresistance effect that appears around zero field 72 , 73 , 76 , 87 . This work aimed to follow the effect of temperature on the observed small and narrow negative magnetoresistance effect, determine whether a weak localization type line-shape analysis succeeds in describing the data, extract physical parameters, and possibly identify the physical origin of the observed effect.…”

“…Our magnetotransport studies have been characterized by two distinct negative magnetoresistance effects in the high quality GaAs/AlGaAs 2DES in the low magnetic field limit: (a) a negative Giant Magneto-Resistance (GMR) effect over larger magnetic fields (−0.15 ≤ B ≤ 0.15 T ) and (b) a small and narrow negative magnetoresistance effect in the immediate vicinity of null magnetic field. The dependence of the negative-GMR on the sample size, DC-bias, temperature, and also the interplay between GMR and the radiation induced magnetoresistance oscillations have been reported 72 , 76 , 87 . Here, we present the experimental study of the small and narrow negative magnetoresistance effect about B = 0.…”

B-periodic oscillations in the Hall-resistance induced by a dc-current-bias under combined microwave-excitation and dc-current bias in the GaAs/AlGaAs 2D system

“…The requirement of a dc -bias for the observability of the effect, together with the improved observability of the effect at higher bath temperatures, T ≈ 4 K, suggests that the dc -bias serves to heat the electron system, and the current heating helps to bring about the obervability of the effect. Certainly, the observed effects are fascinating and further measurements are being carried out to understand their origin, and the role of the dc -bias in the electronic system 30 , 31 .…”

Influence of Microwave Excitation‐Power on the Narrow Negative Magnetoresistance Effect Around B = 0 T in the Ultra‐High Mobility GaAs/AlGaAs 2DES

“…As far as the dark magnetoresistance properties of high mobility GaAs/AlGaAs 2DES are concerned, our previous reports exhibit two distinct dark MR effects, which are: 1) negative Giant Magnetoresistance (negative‐GMR) effect and 2) narrow negative MR effect around B = 0 T. Experimental studies have shown that the negative‐MR effect around zero magnetic fields is temperature dependent (i.e., T ≥ 1 K) . However, another study reported a temperature (i.e., T ≤ 800 mK) invariance of the narrow negative magnetoresistance effect .…”