Hall-conductivity sign change and fluctuations in amorphous (formula presented) films

Abstract

The sign change in the Hall conductivity has been studied in thin amorphous (formula presented) films. By changing the film thickness it is shown that the field at which the sign reversal occurs shifts to lower values (from above to below the mean-field transition field (formula presented) with increasing film thickness. This effect can be understood in terms of a competition between a positive-normal and a negative-fluctuation contribution to the Hall conductivity. © 2001 The American Physical Society.