Microwave Transmission Measurements in Gated GaAs/AlGaAs Quantum Wells

Microwave transmission measurements across a 2D electron system have been previously demonstrated in quantum Hall effect and electronic solids regime [1].~We have developed a co-planar waveguide (CPW) system for experiments in microwave-induced resistance oscillations and zero resistance states. Microwaves from a tunable source (2 - 40 GHz) were fed into our system and coupled to a CPW meander line at 300mK to measure cyclotron resonance peaks from a carbon-doped (100) GaAs/Al$_{x}$Ga$_{1-x}$As quantum well 2D hole system.~Our samples are Hall bars with mobility $\mu $= 0.7-1 $\times $10$^{6}$ cm$^{2}$/Vs and carrier density ranging from 2.02 - 2.26$\times $10$^{11}_{ }$cm$^{-2}$. Each sample has been gated with AuPd using a Si$_{3}$N$_{4}$ dielectric.~A differential power measurement $\Delta \mbox{P }=\mbox{ P}_{\mbox{out}} \mbox{-P}_{\mbox{out}}^{\mbox{gate}} $is taken with the signal from the power sensor triggered from a modulated gate to remove the background microwave signal, yielding a cyclotron resonance peak from the transmission signal.~We are able to fit our cyclotron transmission signal using the Drude model and determine the hole mass and the cyclotron scattering time. Experimental data as well as a brief discussion will be presented. The work at Rice was funded by NSF DMR-0706634. [1] L. W. Engel et al, Phys. Rev. Lett. 71, 2638 (1993).