Scaling analysis of the magnetic-field-tuned quantum transition in superconducting amorphous In-O films

Abstract

We have studied the magnetic-field-tuned superconductor-insulator quantum transition (SIT) in amorphous In-O films with different oxygen content and, hence, different electron density. While for states of the film near the zero-field SIT the two-dimensional scaling behaviour is confirmed, for deeper states in the superconducting phase the SIT scenario changes: in addition to the scaling function that describes the conductivity of fluctuation-induced Cooper pairs, there emerges a temperature-dependent contribution to the film resistance. This contribution can originate from the conductivity of normal electrons.