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Quantum melting on a lattice and a delocalization transition

A.L. Efros and E.V. Tsiper

Department of Physics, University of Utah, Salt Lake City, UT 84112
We consider 1D and 2D gas of spinless fermions with the Coulomb and the short range interactions on a square lattice at T=0. Using exact diagonalization technique we study finite clusters with up to 16 and in some cases up to 20 particles at filling factors nu=1/2 and 1/6. By increasing the hopping amplitude we obtain the low-energy spectrum of the system in a wide range from the classical Wigner crystal to almost free gas of fermions. The most efforts are made to study the mechanism of the structural and insulator-metal transitions. We show that both transitions are determined by the energy band of the defect with the lowest energy in the Wigner crystal.

1997 Int. Conference on Strongly Coupled Coulomb Systems, Boston, August 3-10, 1997.
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