title: Band structures built by the elongation method.
abstract: A recently proposed approach for extracting band structures from finite-cluster calculations is improved so that (avoided) band crossings can be handled and the problems related to so-called doublings and holes are reduced. In particular, we demonstrate how the method can be combined with the elongation method for the finite-system calculations and apply it to extracting band structures for polymers from oligomer calculations. As illustrations of the approach we discuss a chain of water molecules, polyacetylene, polyethylene, and a BN nanotube without and with an impurity.
authors.affiliation: Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan.
authors.forename: Anna
authors.initials: A
authors.lastname: Pomogaeva
authors.forename: Michael
authors.initials: M
authors.lastname: Springborg
authors.forename: Bernard
authors.initials: B
authors.lastname: Kirtman
authors.forename: Feng Long
authors.initials: FL
authors.lastname: Gu
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Aoki