First-principles study of the structures and electronic band properties of Bi 2 Te 3 { 0 1 1 ̄ 5 } nanoribbons

Abstract

Bi2Te3 is known to be an excellent thermoelectric material as well as a topological insulator. We prepare Bi 2 Te 3 { 0 1 1 ̄ 5 } nanosheets with a hydrothermal method and find that the interplanar spacings have a little difference though they belong to a same family of crystal planes. Then, we investigate the structural and electronic properties of Bi 2 Te 3 { 0 1 1 ̄ 5 } nanoribbons with one to six atomic layers by density-functional theory. The results indicate that the nanoribbons exhibit insulator with a band gap except the three-atomic-layer ribbon, which unexpectedly shows a metallic behavior with a gapless band structure.