Diamond-type structure allotrope { \alpha}-Sn is attracting much attention as a topological Dirac semimetal (TDS). In this study, we demonstrate that { \alpha}-Sn undergoes a phase transition to another allotrope { \beta}-Sn with superconductivity at low temperature by irradiating with a focused Ga ion beam (FIB). To clarify the transition mechanism, we performed X-ray photoemission spectroscopy (XPS) measurements on an { \alpha}-Sn thin film irradiated with FIB and an as-grown { \alpha}-Sn thin film. The XPS results suggest that the local annealing, which is one of the side effects of FIB, causes the transformation from { \alpha}-Sn into { \beta}-Sn. Furthermore, the difference in the chemical states between { \alpha}-Sn and { \beta}-Sn can be quantitatively explained by the crystal structures rather than the degree of metallicity reflecting the conductivity. These results propose a new way of fabricating TDS/superconductor in-plane heterostructures based on { \alpha}-Sn and { \beta}-Sn.
Categories: cond-mat.mtrl-sci