Radio-frequency reflectometry on large gated 2-dimensional systems
  We have embedded an AlGaAs/GaAs based, gated 2D hole system (2DHS) into an impedance transformer $LC$ circuit, and show that by using radio-frequency reflectometry it is possible to perform sensitive, large bandwidth, electrical resistance measurements of 2D systems at mK temperatures. We construct a simple lumped element model where the gated 2DHS is described as a resistive transmission line. The model gives a qualitative understanding of the experimental results. As an example, we use our method to map out the Landau level evolution in a 2DHS as a function of magnetic field and gate voltage. 
L.J. Taskinen, R.P. Starrett, T.P. Martin, A.P. Micolich, A.R.   Hamilton, M.Y. Simmons, D.A. Ritchie, and M. Pepper