Theory of the magnetic-field-induced metal-insulator transition

We study the properties of electronic systems in the presence of a magnetic field. For the quasi-one-dimensional chain, the magnetic-field-induced metal-insulator transitions are investigated with uniform and nonuniform magnetic flux, respectively. For the two-dimensional square lattice, metal-insulator transitions can be achieved at both zero and nonzero temperatures when staggered magnetic flux is turned on. Moreover, a pesudogap is opened on the two-dimensional square Fermi surface. When we introduce fluctuations into the perfect staggered magnetic field and increase its magnitude, a finite region of the Fermi surface around (π/2,π/2) would be gradually formed with decreasing bandwidth. For both one- and two-dimensional cases, the temperature and flux dependence of the induced currents are obtained and it is shown that the current state with staggered flux distribution in two dimensions is stable.