1997/10/12 by M. Y. Simmons, A. R. Hamilton, T. G. Griffiths +4
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1016/s0921-4526(98)00296-8
4 pages, latex, 4 postscript figures, submitted to EP2DS-12 on 21st August 1997, to appear in Physica B
arxiv created 1997/10/12 · openalex publication_date 1998/06/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We have observed a metal-insulator transition in an ultra-low density two dimensional hole gas formed in a high quality GaAs-AlGaAs heterostructure at B=0. At the highest carrier density studied (ps=2.2x1010 cm-2, rs=16) the hole gas is strongly metallic, with an exceptional mobility of 425,000 cm2V-1s-1. The low disorder and strength of the many-body interactions in this sample are highlighted by the observation of re-entrant metal insulator transitions in both the fractional (ν< 1/3) and integer (2 > ν> 1) quantum Hall regimes. On reducing the carrier density the temperature and electric field dependence of the resistivity show that the sample is still metallic at ps=1.3x1010 cm-2 (rs=21), becoming insulating at ps≃1x1010 cm-2. Our results indicate that electron-electron interactions are dominant at these low densities, pointing to the many body origins of this metal-insulator transition. We note that the value of rs at the transition (rs=23 +/- 2) is large enough to allow the formation of a weakly pinned Wigner crystal, and is approaching the value calculated for the condensation of a pure Wigner crystal.