Cu-Doped KCl Unfolded Band Structure and Optical Properties Studied by DFT Calculations
| Autor: | José Luis Cabellos, Raul Aceves, Cesar Castillo-Quevedo, Roberto Núñez-González, Alvaro Posada-Amarillas |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
unfolding band structure general_materials_science Primitive cell 02 engineering and technology Electronic structure DFT calculations lcsh:Technology 01 natural sciences Molecular physics Article KCl Pseudopotential Condensed Matter::Materials Science 0103 physical sciences General Materials Science optical spectrum lcsh:Microscopy 010306 general physics Electronic band structure Basis set lcsh:QC120-168.85 Valence (chemistry) lcsh:QH201-278.5 Dopant Quantitative Biology::Neurons and Cognition lcsh:T Doping 021001 nanoscience & nanotechnology ABINIT Brillouin zone lcsh:TA1-2040 Crystal field theory lcsh:Descriptive and experimental mechanics Density functional theory lcsh:Electrical engineering. Electronics. Nuclear engineering lcsh:Engineering (General). Civil engineering (General) 0210 nano-technology lcsh:TK1-9971 |
| Zdroj: | Materials Volume 13 Issue 19 Materials, Vol 13, Iss 4300, p 4300 (2020) |
| Popis: | We computed the optical properties and the folded and unfolded band structure of Cu-doped KCl crystals. The calculations use the plane-wave pseudo-potential approach implemented in the ABINIT electronic structure package within the first-principles density-functional theory framework. Cu substitution into pristine KCl crystals requires calculation by the supercell (SC) method from a theoretical perspective. 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 cuprous ion (Cu+) on electronic properties; We unfolded the band structure of SC KCl:Cu to directly compare 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. As a result, we identified those interband transitions that give rise to the absorption peaks due to the Cu ion. These transitions include valence and conduction bands formed by the Cu-3d and Cu-4s electronic states. To investigate the effects of doping position, we consider different doping positions, where the Cu dopant occupies all the substitutional sites replacing host K cations. Our results indicate that the doping position's effects give rise to two octahedral shapes in the geometric structure. The distorted-twisted octahedral square bipyramidal geometric-shape induces a difference in the crystal field splitting energy compared to that of the perfect octahedral square bipyramidal geometric-shape. |
| Databáze: | OpenAIRE |
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