In-plane magnetic-field-induced Kosterlitz-Thouless-type metal-insulator transition incoupled double quantum wells

We study the localization properties in coupled double quantum wells with an in-plane magnetic field. The localization length is directly calculated using a transfer matrix technique and finite-size scaling analysis. We show that the system maps into a two-dimensional XY model and undergoes a disorder-driven Kosterlitz-Thouless-type metal-insulator transition depending on the coupling strength between the two-dimensional layers and the magnitude of the in-plane magnetic field. For a system with fixed disorder, the metallic regime appears to be a window to the magnetic field-coupling strength plane. Experimental implications of the transition will be discussed.