Affiliation
National High Magnetic Filed Laboratory
Title
Wigner solids in high-quality p-GaAs/AlGaAs studied by surface acoustic wave technique
Abstract
A. V. Suslov$^{1,*}$, I. L. Drichko$^2$, I. Yu. Smirnov$^2$, K. W. Baldwin$^3$, L. N. Pfeiffer$^4$, K. W. West$^4$, and Y. M. Galperin$^{2,5}$
$^1$National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
$^2$Ioffe Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia
$^3$Princeton Materials Institute, Princeton University, Princeton, New Jersey 08544, USA
$^4$Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
$^5$Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo, Norway
*corresponding author: @email
Our study focused on analysing the complex ac conductivity ($σ_{ac}=σ_1 - iσ_2$) of a 17 nm wide single p-GaAs/AlGaAs quantum well with a hole concentration of approximately 1.2$\cdot$10$^{11}$ cm$^{−2}$ and mobility of approximately 1.8$\cdot$10$^{6}$ cm$^{2}$/Vs. We calculated conductivity of 2D holes from simultaneously measured the absorption and velocity of surface acoustic waves (SAWs) propagating along the interface between a piezoelectric crystal and the two-dimensional hole system under investigation. Our measurements taken in magnetic fields up to 18 T at SAW frequencies ranging from 30 MHz to 300 MHz, temperatures from 20 mK to 300 mK, showed the presence of integer and fractional quantum Hall effects.
Evolution of ac conductivity in the vicinity of observed quantum oscillations at the filling factors $\nu$ = 1 (B = 5.34 T) and $\nu$ = 1/3 (B = 16.1 T) corresponds to the formation of the domains of a pinned Wigner crystal, i.e., a Wigner solid. Although the Wigner solid has been previously observed in 2D p-GaAs/AlGaAs hole systems, we were able to detect it at the highest hole density and, consequently, the lowest hole-hole interaction ever reported.