title: The excitonic effects in single and double-walled boron nitride nanotubes.
abstract: The electronic structures and excitonic optical properties of single- and double-walled armchair boron nitride nanotubes (BNNTs) [e.g., (5,5) and (10,10), and (5,5)@(10,10)] are investigated within many-body Green's function and Bethe-Salpeter equation formalism. The first absorption peak of the double-walled nanotube has almost no shift compared with the single-walled (5,5) tube due to the strong optical transition in the double-walled tube that occurs within the inner (5,5) one. Dark and semi-dark excitonic states are detected in the lower energy region, stemming from the charge transfer between inner and outer tubes in the double-walled structure. Most interestingly, the charge transfer makes the electron and the hole reside in different tubes. Moreover, the excited electrons in the double-walled BNNT are able to transfer from the outer tube to the inner one, opposite to that which has been observed in double-walled carbon nanotubes.
authors.affiliation: Department of Physics and Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Shudong
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Physics and Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Yunhai
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Textiles and Clothing, Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
authors.forename: Joanne
authors.initials: J
authors.lastname: Yip
authors.affiliation: Department of Physics and Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 211189, China.
authors.forename: Jinlan
authors.initials: J
authors.lastname: Wang