AlO_x/LiF composite protection layer for Cr-doped(Bi,Sb)_2Te_3 quantum anomalous Hall films

We have realized robust quantum anomalous Hall samples by protecting Cr-doped(Bi,Sb)_2Te_3 topological insulator films with a combination of LiF and A1O_x capping layers.The AlO_x/LiF composite capping layer well keeps the quantum anomalous Hall states of Cr-doped(Bi,Sb)_2Te_3 films and effectively prevent them from degradation induced by ambient conditions.The progress is a key step towards the realization of the quantum phenomena in heterostructures and devices based on quantum anomalous Hall system.     

Tuning the Mottness in Sr3Ir2O7 via Bridging Oxygen Vacancies

The electronic evolution of Mott insulators into exotic correlated phases remains puzzling, because of electron interaction and inhomogeneity. Introduction of individual imperfections in Mott insulators could help capture the main mechanism and serve as a basis to understand the evolution. Here we utilize scanning tunneling microscopy to probe the atomic scale electronic structure of the spin-orbit-coupling assisted Mott insulator Sr₃Ir₂O₇. It is found that the t...