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TT: Tiefe Temperaturen

TT 16: Posters Correlated Electrons, Measuring Devices, Cryotechnique

TT 16.25: Poster

Samstag, 5. März 2005, 11:00–16:30, Poster TU C

Delocalization of electrons in disordered films induced by parallel magnetic field and film thickness — •R.K. Brojen Singh, V.Z. Cerovski, and M. Schreiber — Institut für Physik, Technische Universität, D-09107 Chemnitz, Germany

We present results of the investigation of delocalization of non-interacting electrons in disordered thin films induced by parallel magnetic field B and film thickness b. We compare two procedures within the framework of self-consistent theory of localization for weak fields generalized to situations lacking time reversal invariance by (a) taking the diffusion constants, D^pp and D^ph corresponding to particle-particle and particle-hole channels respectively as equal, and (b) taking D^pp≠ D^ph. The two procedures give different results, the main one being that (a) gives the metal-insulator transition (MIT) at T=0 induced by the magnetic field and film thickness, but (b) does not. In the insulating regime we find the localization length as a function of B, b and λ (disorder strength) and calculate critical values of B, b and λ. In the metallic regime we calculate conductivity as a function of these parameters. At T>0 both procedures give an MIT.