Signatures of an intermediate 2d Coulomb phase at low temperatures
CEA, Service de Physique de l'Etat Condensé,
Centre d'Etudes de Saclay
F-91191 Gif-sur-Yvette Cedex, France
Accepted: 9 May 2000
The study of the ground state of spinless fermions in 2d disordered clusters (Phys. Rev. Lett., 83 (1999) 1826) has suggested the existence of a new quantum phase for intermediate Coulomb energy to kinetic energy ratios rs. Exact diagonalization of the same small clusters shows that its low-energy excitations (quantum ergodicity above a few “hexatic” excitations characterized by oriented currents) significantly differ from those occurring in the Fermi glass (weak rs) and in the pinned Wigner crystal (large rs). The “hexatic” excitations vanish for temperatures of order of the Fermi temperature.
PACS: 71.30.+h – Metal-insulator transitions and other electronic transitions / 71.27.+a – Strongly correlated electron systems, heavy fermions / 72.15.Rn – Localization effects (Anderson or weak localization)
© EDP Sciences, 2000