Investigation of properties in barium chalcogenides from first-principles calculations

Abstract

The structural and electronic properties in barium chalcogenides were systematically investigated from first-principles calculations. Different electronic properties were observed between barium chalcogenides with and without oxygen. The results were attributed to the high ionic bonds between barium and oxygen, as compared to all other chemical bonds between barium and group VI elements. Since an introduction of oxygen into barium chalcogenides not containing oxygen was found to be able to adjust the energy gap accordingly, the absorption of oxygen on BaTe(111) surface was investigated theoretically. The results showed that a vacancy or oxygen atom on a tellurium site was stable on the Ba-rich BaTe(111) surface while a vacancy or tellurium atom on a barium site was stable on the Te-rich BaTe(111) surface. It was worth experimental attempt to synthesize new wide-band-gap semiconductors by absorption of oxygen on Ba-rich BaTe(111) thin film.