A microscopic study investigating the structure of SnSe surfaces

SnSe has been widely studied due to its many potential applications that take advantage of its excellent thermoelectric, photovoltaic, and optoelectronic properties. However, experimental investigations into the microscopic structure of SnSe remain largely unexplored. Herein, for the first time, the atomic and electronic structures of SnSe surfaces are studied by a home-built low temperature scanning tunneling microscope (STM) and density functional theory (DFT) calculations. The cleaved surface of SnSe is comprised of covalently bonded Se and Sn atoms in zigzag patterns. However, rectangular periodicity was observed in the atomic images of SnSe surfaces for filled and empty state probing. Detailed atomic structures are analyzed by DFT calculations, indicating that the bright extrusions of both filled and empty state images are mostly located at the positions of Sn atoms. [Display omitted] •The atomic and electronic structures of SnSe surfaces are studied by a home-built LT-STM and DFT calculations.•Clear atomic images of cleaved SnSe surfaces were observed at the filled and empty state measurements.•The atomic structures revealed the periodicity of a rectangular unit cell, and detail structures were analyzed based on DFT.•Only Sn atoms are visible on STM topographic images for both filled and empty state probing.