Wednesday, November 21, 2012

1211.4690 (Chi-Cheng Lee et al.)

Unfolding first-principles band structures with a non-orthogonal basis
set: a study on surface and vacancy states of ZrB$_2$
   [PDF]

Chi-Cheng Lee, Yukiko Yamada-Takamura, Taisuke Ozaki
Current computational capability allows a large scale first-principles calculation, however, the heavily folded electronic band structure due to a big supercell suppresses an easy visualization of the effect of symmetry breakers introduced to the reference system. While an unfolding method has been proposed, a general formula is not yet available for a basis set of non-orthogonal atomic-like orbitals that is ideal for the unfolding concept due to the translational symmetric nature. In this study, we derive a simple formula applicable for both orthogonal and non-orthogonal localized orbitals. Codes using a basis set of linear combination of atomic-like orbitals, where the order-$N$ method can be implemented much easier, can benefit from this approach in unfolding band structures. This method is applied for analysis of surface state with ZrB$_2$(0001) surface and provides a straightforward way to examine how good a surface-sensitive measurement, like ARPES, can represent the bulk property. The effect of vacancies at various concentration levels in ZrB$_2$ will also be discussed.
View original: http://arxiv.org/abs/1211.4690

No comments:

Post a Comment