Evidence for A Two-dimensional Quantum Wigner Solid in Zero Magnetic Field

We report the first experimental observation of a characteristic nonlinear threshold behavior from dc dynamical response as an evidence for a Wigner crystallization in high-purity GaAs 2D hole systems in zero magnetic field. The system under increasing current drive exhibits voltage oscillations with negative differential resistance. They confirm the coexistence of a moving crystal along with striped edge states as observed for electrons on helium surfaces. However, the threshold is well below the typical classical levels due to a different pinning and depinning mechanism that is possibly related to a quantum process

Photovoltage Detection of Edge Magnetoplasmon Oscillations and Giant Magnetoplasmon Resonances in A Two-Dimensional Hole System

In our high mobility p-type AlGaAs/GaAs two-dimensional hole samples, we originally observe the B-periodic oscillation induced by microwave (MW) in photovoltage (PV) measurements. In the frequency range of our measurements (5 - 40 GHz), the period ({\Delta}B) is inversely proportional to the microwave frequency (f). The distinct oscillations come from the edge magnetoplasmon (EMP) in the high quality heavy hole system. In our hole sample with a very large effective mass, the observation of the EMP oscillations is in neither the low frequency limit nor the high frequency limit, and the damping of the EMP oscillations is very weak under high magnetic fields. Simultaneously, we observe the giant plasmon resonance signals in our measurements on the shallow two-dimensional hole system (2DHS)

Oscillatory Magneto-Thermopower and Resonant Phonon Drag in a High-Mobility 2D Electron Gas

Experimental and theoretical evidence is presented for new low-magnetic-field ($B<5$ kG) 1/B-oscillations in the thermoelectric power of a high-mobility GaAs/AlGaAs two-dimensional (2D) electron gas. The oscillations result from inter-Landau-Level resonances of acoustic phonons carrying a momentum equal to twice the Fermi wavenumber at $B = 0$. Numerical calculations show that both 3D and 2D phonons can contribute to this effect.Comment: 4 pages, 5 figure