Scanning probe microscopy induced surface modifications of the topological insulator BiTe in different environments.

We investigated the topological insulator (TI) BiTe in four different environments (ambient, ultra-high vacuum (UHV), nitrogen gas and organic solvent environment) using scanning probe microscopy (SPM) techniques. Upon prolonged exposure to ambient conditions and organic solvent environments the cleaved surface of the pristine BiTe is observed to be strongly modified during SPM measurements, while imaging of freshly cleaved BiTe in UHV and nitrogen gas shows considerably less changes of the BiTe surface. We conclude that the reduced surface stability upon exposure to ambient conditions is triggered by adsorption of molecular species from ambient, including HO, CO, etc which is verified by Auger electron spectroscopy. Our findings of the drastic impact of exposure to ambient on the BiTe surface are crucial for further in-depth studies of the intrinsic properties of the TI BiTe and for potential applications that include room temperature TI based devices operated under ambient conditions.