Role of basis sets on the unfolding of supercell band structures: From tight-binding to density functional theory
1 Istituto per la Microelettronica e Microsistemi (CNR-IMM) - Z.I. VIII strada 5, 95121 Catania, Italy
2 Dipartimento di Fisica e Astronomia, Università di Catania - Via Santa Sofia 64, 95125 Catania, Italy
Received: 15 April 2014
Accepted: 29 June 2014
We develop a simple and fast procedure that unfolds band structures obtained from supercell calculations and which is valid for methods based on the linear combination of atomic orbitals, regardless of basis orthogonality. We show that by appropriately choosing the localized basis set, the unfolding formula reduces to a product of selective sums between expansion coefficients. The approach can be directly applied to supercells without the creation of virtual crystals, while it can be further simplified when working directly on the primitive Brillouin zone. Density functional theory examples are given for both ideal and defected systems.
PACS: 71.20.-b – Electron density of states and band structure of crystalline solids / 71.15.Dx – Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)
© EPLA, 2014