Negative compressibility of interacting two-dimensional electron and quasiparticle gases

Strongly interacting two-dimensional Bose gases.

We prepare and study strongly interacting two-dimensional Bose gases in the superfluid, the classical Berezinskii-Kosterlitz-Thouless (BKT) transition, and the vacuum-to-superfluid quantum critical regimes. A wide range of the two-body interaction strength 0.05 < g < 3 is covered by tuning the scattering length and by loading the sample into an optical lattice. Based on the equations of state m...

Tunneling between parallel two-dimensional electron gases.

The tunneling between two parallel two-dimensional electron gases has been investigated as a function of temperature T , carrier density n, and the applied perpendicular magnetic field B. In zero magnetic field the equilibrium resonant lineshape is Lorentzian, reflecting the Lorentzian form of the spectral functions within each layer. From the width of the tunneling resonance the lifetime of th...

InGaAs/GaAsSb based two-dimensional electron gases

Nonlinear screening in two-dimensional electron gases.

We have performed self-consistent calculations of the nonlinear screening of a point charge Z in a two-dimensional electron gas using a density functional theory method. We find that the screened potential for a Z=1 charge supports a bound state even in the high-density limit where one might expect perturbation theory to apply. To explain this behavior, we prove a theorem to show that the resul...

Freely suspended two - dimensional electron gases

We present a new technique allowing us to build freely suspended two-dimensional electron gases from AlGaAs/GaAs/AlAs heterostructures. This technique relies on an MBE-grown structures that includes a sacrificial layer. ( 1998 Elsevier Science B.V. All rights reserved.