Electron heating induced by an ac-bias current in the regime of Shubnikov–de Haas oscillation in the high mobility GaAs/Al x Ga1−x As two-dimensional electron system

The reflected microwave power from the photo-excited high mobility GaAs/AlGaAs 2D device has been measured over the wide frequency band spanning from 30 to 330 GHz simultaneously along with diagonal magnetoresistance as a function of the magnetic field. Easily distinguishable resonances in the reflected power signal are observed at the same magnetic fields as a reduced amplitude in the Shubnikov-de Haas (SdH) oscillations of the diagonal magnetoresistance. The reflection resonances with concurrent amplitude reduction in SdH oscillations are correlated with cyclotron resonance induced by microwave, mm-wave, and terahertz photoexcitation. The magnetoplasma effect was also investigated. The results suggest a finite frequency zero-magnetic-field intercept, providing an estimate for the plasma frequency. The experimentally measured plasma frequency appears to be somewhat lower than the estimated plasma frequency for these Hall bars. The results, in sum, are consistent with an effective mass ratio of m*/m = 0.067, the standard value, even in these high mobility GaAs/AlGaAs devices, at very large filling factors. Preliminary findings from this article have been published as conference proceedings, see Kriisa, A., et al., J. of Phys. Conf. Ser. 864, 012057 (2017).

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Cyclotron resonance in the high mobility GaAs/AlGaAs 2D electron system over the microwave, mm-wave, and terahertz- bands

Kriisa

Samaraweera

Heimbeck

et al. 2019

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Radiation-induced magnetoresistance oscillations in monolayer and bilayer graphene

Mani

Kriisa

Munasinghe

2019

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We examine the characteristics of the microwave/mm-wave/terahertz radiation-induced magnetoresistance oscillations in monolayer and bilayer graphene and report that the oscillation frequency of the radiation-induced magnetoresistance oscillations in the massless, linearly dispersed monolayer graphene system should depend strongly both on the Fermi energy, and the radiation frequency, unlike in the case of the massive, parabolic, GaAs/AlGaAs 2D electron system, where the radiation-induced magnetoresistance oscillation frequency depends mainly on the radiation frequency. This possible dependence of the magnetoresistance oscillation frequency on the Fermi level at a fixed radiation frequency also suggests a sensitivity to the gate voltage in gated graphene, which suggests an in - situ tunable photo-excitation response in monolayer graphene that could be useful for sensing applications. In sharp contrast to monolayer graphene, bilayer graphene is expected to show radiation-induced magnetoresistance oscillations more similar to the results observed in the GaAs/AlGaAs 2D system. Such expectations for the radiation-induced magnetoresistance oscillations are presented here to guide future experimental studies in both of these modern atomic layer material systems.

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Electron heating induced by microwave photoexcitation in the GaAs/AlGaAs two-dimensional electron system

et al. 2018

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We examined the influence of microwave radiation on both the amplitude of Shubnikov-de Haas (SdH) oscillations and the null field longitudinal magnetoresistance at liquid helium temperatures, in GaAs/AlGaAs Hall bar devices. Microwave radiation over the frequency range 25 ≤ f ≤ 50 GHz with source power 0 ≤ P ≤ 4 mW served to photo-excite the high mobility (10 7 cm 2 /V s) 2D electron system (2DES) as magnetoresistance traces were obtained as a function of the microwave power P and temperature T. Lineshape study of SdH oscillations has been carried out over the span 2.3 < ωc/ω ≤ 5.2, where ωc = eB/m * , ω = 2πf , B is the magnetic field, m * is the effective mass and f is the microwave frequency. Here, fits of the SdH lineshape served to determine the electron temperature (Te) as a function of P and T. Theory has proposed that, in the ωc/ω ≥ 1 regime, both the electron temperature and radiation energy absorption rate (Sp) exhibit relatively small response, while in the ωc/ω ≤ 1 regime, both Te and Sp are enhanced and exhibit oscillatory behavior. We compare the experimental results with these theoretical predictions, and comment upon relative role of electron heating in the microwave photo-excited high mobility 2DES.

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Electron heating induced by an ac-bias current in the regime of Shubnikov–de Haas oscillation in the high mobility GaAs/Al_xGa_1−xAs two-dimensional electron system

Cited by 3 publications

References 97 publications

Cyclotron resonance in the high mobility GaAs/AlGaAs 2D electron system over the microwave, mm-wave, and terahertz- bands

Cyclotron resonance in the high mobility GaAs/AlGaAs 2D electron system over the microwave, mm-wave, and terahertz- bands

Radiation-induced magnetoresistance oscillations in monolayer and bilayer graphene

Electron heating induced by microwave photoexcitation in the GaAs/AlGaAs two-dimensional electron system

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