講演情報
[10a-E203-10]Band-edge localization in large-diameter double-walled boron nitride nanotubes
〇(D)Nadia Sultana1, Yanlin Gao1, Mina Maruyama1, Susumu Okada1 (1.Univ. of Tsukuba)
キーワード：
Boron nitride nanotube、Band edge localization、Nearly free electron state
Boron nitride nanotubes (BNNTs) are insulating, tubular materials used as templates for synthesizing other tubular materials due to their atomically smooth and chemically inert walls [1]. In tubular materials, the curvature plays a decisive role in determining their electronic properties. All single-walled BNNTs are insulators, with band gaps that gradually approach that of flat hexagonal boron nitride [2].Although the curvature effects of single-wall BNNTs on their electronic properties have been well studied, the detailed electronic properties of DW-BNNTs are still unclear. Here, we aim to investigate the electronic properties of DW-BNNTs in terms of inter-wall atomic arrangement using density functional theory.
Fig. 1 shows the band structures of DW-BNNTs whose outer wall diameters are 1.0, 3.0, and 6.0 nm for (5,5)@(10,10), (25,25)@(30,30), and (55,55)@(60,60) BNNTs, respectively. The electronic structure near the band gap is sensitive to the tube diameters: A parabolic band emerges at the conduction band edge and the point for the (5,5)@(10,10)BNNT, while the conduction band edge is located at two-thirds of -X line. In addition, several energy bands near the band edges are isolated from the continuous bands in the large-diameter double-walled BNNT, owing to interwall orbital hybridization that leads to localization of those electron states along the circumference.
Fig. 1 shows the band structures of DW-BNNTs whose outer wall diameters are 1.0, 3.0, and 6.0 nm for (5,5)@(10,10), (25,25)@(30,30), and (55,55)@(60,60) BNNTs, respectively. The electronic structure near the band gap is sensitive to the tube diameters: A parabolic band emerges at the conduction band edge and the point for the (5,5)@(10,10)BNNT, while the conduction band edge is located at two-thirds of -X line. In addition, several energy bands near the band edges are isolated from the continuous bands in the large-diameter double-walled BNNT, owing to interwall orbital hybridization that leads to localization of those electron states along the circumference.