Preprint Article Version 1 This version is not peer-reviewed

Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations

Version 1 : Received: 17 July 2020 / Approved: 19 July 2020 / Online: 19 July 2020 (20:22:08 CEST)

How to cite: Castillo-Quevedo, C.; Cabellos, J.L.; Aceves, R.; Núñez-González, R.; Posada-Amarillas, A. Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations. Preprints 2020, 2020070433 (doi: 10.20944/preprints202007.0433.v1). Castillo-Quevedo, C.; Cabellos, J.L.; Aceves, R.; Núñez-González, R.; Posada-Amarillas, A. Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations. Preprints 2020, 2020070433 (doi: 10.20944/preprints202007.0433.v1).

Abstract

The unfolded band structure and optical properties of Cu-doped KCl crystals were computed by first principles within the framework of density functional theory, implemented in the ABINIT electronic structure package utilizing pseudopotential approximation and a plane-wave basis set. From a theoretical point of view, Cu substitution into pristine KCl crystals requires calculation by the supercell (SC) method. This procedure shrinks the Brillouin zone, resulting in a folded band structure that is difficult to interpret. To solve this problem and gain insight into the effect of copper ions (Cu+) on electronic properties, the band structure of SC KCl:Cu was unfolded to make a direct comparison with the band structure of the primitive cell (PC) of pristine KCl. To understand the effect of Cu substitution on optical absorption, we calculated the imaginary part of the dielectric function of KCl:Cu through a sum-over-states formalism and broke it down into different band contributions by partially making an iterated cumulative sum (ICS) of selected valence and conduction bands. Consequently, we identified those interband transitions that give rise to the absorption peaks due to the Cu+ ion. These transitions involve valence and conduction bands formed by the Cu-3d and Cu-4s electronic states

Subject Areas

DFT calculations; unfolding band structure; optical spectrum; KCl