Antisites, Antistructures, and Bond-Switching Reactions in Layered Chalcogenides

摘要

State of the art ab inito total-energy calculations are used to investigate the properties of a large number of antisite and antistructure defects in c-As2Se3. Calculations of their formation energies are made, and an examination of their electronic states and relaxed geometries is performed. Surprisingly it is found that a select set of the antistructures undergoes bond-switching reactions that give rise to a news peculiar class of defects. These bond-switched antistructure defects are found to have lower formation energies than any of the antistructures. One of these is of particular interest as it forms a bridging bond between the layers of c-AsSe3. This cross-linking defect (CLD) is examined in more detail. It is found that the associated bond-switching reaction proceeds with small or no barrier for most charge states. This is surprising as the atomic movements associated with the formation of the CLD are quite large. Arsenic, Selenium, Reprints. (mjm)