Atomic disorders in layer structured topological insulator SnBi2Te4 nanoplates

摘要

Identification of atomic disorders and their subsequent control has proven to be a key issue in predicting,understanding,and enhancing the properties of newly emerging topological insulator materials.Here,we demonstrate direct evidence of the cation antisites in single-crystal SnBi2Te4 nanoplates grown by chemical vapor deposition,through a combination of sub-(a)ngstr(o)m-resolution imaging,quantitative image simulations,and density functional theory calculations.The results of these combined techniques revealed a recognizable amount of cation antisites between Bi and Sn,and energetic calculations revealed that such cation antisites have a low formation energy.The impact of the cation antisites was also investigated by electronic structure calculations together with transport measurement.The topological surface properties of the nanoplates were further probed by angle-dependent magnetotransport,and from the results,we observed a two-dimensional weak antilocalization effect associated with surface carriers.Our approach provides a pathway to identify the antisite defects in ternary chalcogenides and the application potential of SnBi2Te4 nanostructures in next-generation electronic and spintronic devices.