Temperature dependence of magneto-optical Kerr signal in GeTe - Sb2Te3 topological superlattice

Abstract

In this report, we studied the temperature dependence of magneto-optical Kerr rotation in [(GeTe)2/(Sb2Te3)1]n=8 topological superlattice from room temperature to 440 K. At temperatures lower than a threshold temperature of 360 K, the Kerr signal was negligible. On the other hand, at temperatures higher than the threshold, two resonant Kerr peaks with a mirror-symmetry for one field scan from + 20 to - 20 kOe were observed. We found that the resonant field of each Kerr signal peak is gradually decreased with increasing the temperature, while its magnitude is increased. We further found that a phase transition from the high temperature phase to a low temperature phase can be controlled by an external magnetic field.