Dimensional and temperature dependence of metal-insulator transition in correlated and disordered systems

¹  Institute of Mathematical Sciences - 600113, Chennai, India
²  S. N. Bose National Centre for Basic Sciences - Kolkata, India

Corresponding authors: trbkrm01@yahoo.co.in tgupta@imsc.res.in sanjay1@bose.res.in

Received: 4 May 2009
Accepted: 18 September 2009

Abstract

We study the dimensional dependence of the interplay between correlation and disorder in two dimensions at half-filling using the 2D disordered Hubbard model with deterministic disorder both at zero and finite temperatures. Inclusion of t' without disorder leads to a metallic phase at half-filling below a certain critical value of U. Above this critical value U_c correlation favours an antiferromagnetic phase. Since disorder leads to double occupancy over the lower-energy site, the competition between Hubbard U and disorder leads to the emergence of a metallic phase, which can be quantified by the calculation of Kubo conductivity, gap at half-filling, density of states, spin order parameter, inverse participation ratio (IPR) and bandwidth. We have studied the effect of disorder on the system in a very novel way through a deterministic disorder which follows a Fibonacci sequence. The behaviour of different quantities shows interesting features on going from a two- to quasi–one-dimensional system.