Experimental study of the Ioffe-Regel criterion for amorphous indium oxide films

Abstract

The Ioffe-Regel criterion predicts the existence of a metal-insulator transition in a film series when the parameter satisfies the criterion ; here is the Fermi wavenumber and is the elastic mean free path of the carriers. According to this criterion, films having are metallic, while films having are insulating. We experimentally observe the metal-insulator transition in amorphous indium oxide films at . The values of were calculated from room temperature resistivity and Hall voltage measurements, while the metal-insulator transition was determined from low-temperature resistivity data using the `w'-criterion of Mobius and of Zabrodskii and Zinov'eva.