Theory of the magnetic-field-induced metal-insulator transition - art. no.174434

We study the properties of electronic systems in the presence of a magnetic field. For the quasi-one-dimensional chain, the magnetic-field-induced met al-insulator transitions are investigated with uniform and nonuniform magne tic flux, respectively. For the two-dimensional square lattice, metal-insul ator transitions can be achieved at both zero and nonzero temperatures when staggered magnetic flux is turned on. Moreover, a pseudogap is opened on t he two-dimensional square Fermi surface. When we introduce fluctuations int o the perfect staggered magnetic field and increase its magnitude, a finite region of the Fermi surface around (pi /2,pi /2) would be gradually formed with decreasing bandwidth. For both one- and two-dimensional cases, the te mperature and flux dependence of the induced currents are obtained and it i s shown that the current state with staggered flux distribution in two dime nsions is stable.