Volume 88, Number 1, October 2009
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||22 October 2009|
Dimensional and temperature dependence of metal-insulator transition in correlated and disordered systems
Institute of Mathematical Sciences - 600113, Chennai, India
2 S. N. Bose National Centre for Basic Sciences - Kolkata, India
Accepted: 18 September 2009
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 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.
PACS: 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
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