Binuka Gunawardana

Georgia State University | GSU · Department of Physics and Astronomy

The microwave-induced change in the narrow negative magnetoresistance effect that appears around zero magnetic field in high mobility GaAs/AlGaAs 2DES (≈107 cm2/Vs) is experimentally examined as a function of incident microwave power at a fixed bath temperature. The experimental results indicate that the narrow negative magnetoresistance effect exh...

We perform magneto transport measurements on GaAs/AlGaAs 2D electron system to understand the influence of the microwave photoexcitation on the spin splitting of the Shubnikov-de Haas oscillations at liquid helium temperatures. The aim of the study is to determine the magnitude of the electron heating under microwave photo-excitation by examining o...

There has been much recent interest in the growing large-area single-crystal graphene flakes as an approach for overcoming the relatively low carrier mobility and the multigrain structure observed in Chemical Vapor Deposition (CVD) graphene. One approach for growing large-sized single-crystal graphene by CVD involves limiting the nucleation density...

In addition to the photo‐excited zero‐resistance states and radiation‐induced magnetoresistance oscillations, which can be observed in the high‐quality GaAs/AlGaAs two‐dimensional electron system (2DES), magnetotransport studies of this 2DES also exhibit interesting dark magnetoresistance effects. Here, a narrow negative magnetoresistance (MR) effe...

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 30≤f≤50GHz with source power 0≤P≤4mW served to photoexcite the high mobility (≃1...

A small and narrow negative-magnetoresistance (MR) effect that appears about null magnetic field over the interval −0.025 ≤B≤ 0.025 T in magnetotransport studies of the GaAs/AlGaAs 2D system with μ≈ 107cm2/Vs is experimentally examined as a function of the sample temperature, T. The temperature dependent magnetoresistance data were fit using the Hi...

The magnetotransport properties of the high mobility GaAs/AlGaAs two-dimensional electron gas systems have been examined to determine the influence of the ac current bias on the carrier temperature. The changes in the line shape of Shubnikov de Haas (SdH) oscillations in the longitudinal magnetoresistance (ΔR_xx) were followed as a functi...

Theory has examined the possibility of electron heating by microwave photo-excitation in the large filling factor, low magnetic field limit in a balance-equation scheme that takes into account photon-assisted electron transitions as well as radiation-induced change of the electron distribution for high-mobility two-dimensional systems.[1] The resul...

Microwave radiation-induced magneto-resistance oscillations are examined under bichromatic excitation for various frequency combinations in order to obtain a better understanding of the lineshape observed in the dual excitation experiment of the high mobility GaAs/AlGaAs 2D electron system. Here, we examine superposition- or lack thereof- in the li...

Millimeter wave radiation-induced magnetoresistance oscillations are examined in the GaAs/AlGaAs 2D electron system under bichromatic excitation in order to study the evolution of the oscillatory diagonal magnetoresistance, Rxx as the millimeter wave intensity is changed systematically for various frequency combinations. The results indicate that a...

Under the steady state of microwave excitation, there is a possibility of microwave induced electron heating in the two-dimensional electron system (2DES), due to absorption of energy from the radiation field. Electron-phonon scattering in the 2DES can then dissipate this excess energy onto the host lattice. According to previous studies, the elect...