The crystal structure of rhenium silicide with an anomalous ordered arrangement of vacancies was investigated by utilizing spherical-aberration (Cs)-corrected scanning transmission electron microscopy. Using Cs-corrected imaging, the first direct observations were made of ordered silicon vacancies in thermoelectric rhenium silicide accompanied by anomalously large local thermal vibration (so-called rattling motion) of silicon atoms on their adjacent sites.

Direct Observation of Vacancies and Local Thermal Vibration in Thermoelectric Rhenium Silicide. S.Harada, K.Tanaka, K.Kishida, N.L.Okamoto, N.Endo, E.Okunishi, H.Inui: Applied Physics Express, 2012, 5[3], 035203