Enhancement of Subnikov-de Haas oscillations by microwave radiation

Abstract

We report for the first time that the Subnikov-de Haas (SdH) pattern can be greatly enhanced by recording the changes in the quantum oscillations of magnetoresistance due to microwave radiation. In order to understand the origin of the enhancement, the dependence of the enhanced SdH signal on temperature, microwave frequency and power has been studied. It is concluded that the enhancement can be attributed to the effects of free carrier absorption and the suppression of the nonoscillatory magnetoresistance. The technique shown here can be used to detect the SdH oscillations at relatively high temperature and in samples with moderate mobilities without perturbing the carrier concentration.