Numerical study on magnetoresistance anomaly in AB rings subjected to microwave radiation

Recently, a brand-new phenomenon induced by microwave radiation was observed in AB ring systems. That is, a significantly wide dip appears in the magnetoresistance of AB ring structures in a weak magnetic field range. Its position (strength of a magnetic field) does not depend on the frequency of microwave. It is clearly considered that excitation of conducting electrons by microwave caused these phenomena. In the present study, we attempt to understand these features by means of a simple model. Here, numerical computation was performed as one-body problem by means of tight-binding model including electron–photon interaction. In addition to the above two experimental features, our model reproduced even the experimental fact that the excitation does not happen, namely, the dip does not appear, when the frequency of the microwave is too high.