Dimensional and temperature dependence of metal-insulator transition in correlated and disordered systemsTribikram Gupta1 and Sanjay Gupta2
1 Institute of Mathematical Sciences - 600113, Chennai, India
2 S. N. Bose National Centre for Basic Sciences - Kolkata, India
received 4 May 2009; accepted in final form 18 September 2009; published October 2009
published online 22 October 2009
We study the dimensional dependence of the interplay between correlation and disorder in two dimensions at half-filling using the 2D t- t' 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 Uc 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.
71.10.Fd - Lattice fermion models (Hubbard model, etc.).
71.30.+h - Metal-insulator transitions and other electronic transitions.
71.23.An - Theories and models; localized states.
© EPLA 2009