Magnetic-field induced metal-insulator transition in SrTiO 3 − δ

Metallic samples of SrTiO 3 − δ with charge-carrier densities of n = 8.6 × 10 16 cm −3 and 2.0 × 10 17 cm −3 are shown to exhibit magnetic-field-induced metal–insulator transitions. Landau levels emerge in the magnetic field, and their energy spacing is comparable to the Fermi and thermal energies. A simple parallel-conduction model involving thermally-activated hopping among Landau levels is introduced to describe the data below the metal–insulator transition temperature.