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Ab initio study for the structural, electronic, magnetic, optical, and thermoelectric properties of K 2 OsX 6 (X = Cl, Br) compounds
Author(s) -
Ullah Rehan,
Ali Malak Azmat,
Murtaza G.,
Khan Afzal,
Mahmood Asif
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.5613
Subject(s) - thermoelectric effect , ferromagnetism , magnetic moment , density functional theory , spintronics , condensed matter physics , curie temperature , materials science , ab initio , seebeck coefficient , ab initio quantum chemistry methods , electronic structure , band gap , direct and indirect band gaps , formula unit , optical conductivity , electronic band structure , chemistry , computational chemistry , crystallography , optoelectronics , physics , thermodynamics , crystal structure , organic chemistry , molecule
Summary Density‐functional theory based, first‐principles spin‐polarized calculations of the structural, electronic, magnetic, optical, and thermoelectric characteristics of K 2 OsX 6 (X = Cl, Br) are presented. Structural optimization confirms the stability of these compounds in ferromagnetic phase with curie temperatures of 726 K (K 2 OsCl 6 ) and 557 K (K 2 OsBr 6 ). The calculated formation and cohesive energies present K 2 OsX 6 compounds as thermodynamically stable and strongly bonded. Computed electronic properties explore both the compounds as half‐metallic. In the spin‐up channel, they exhibit semiconducting nature, having direct band gap values of 2.69 eV (K 2 OsCl 6 ) and 2.1 eV (K 2 OsBr 6 ), while in spin‐down configuration, they turn into metals. The calculated ferromagnetic total spins magnetic moment per formula unit is 2.00 μ B for both the compounds with major contributions from Os‐t 2g states. The reasonable values of optical parameters like optical conductance, absorption factor, refractive index, and reflectivity potentially dedicate these compounds for optoelectronic applications. The calculated positive Seebeck coefficient with maximum values of 76.4 μV/K, for K 2 OsCl 6 , and 99.9 μV/K, for K 2 OsBr 6 , represent these compounds as p‐type materials. The proposed compounds may achieve consideration in spintronic, thermoelectric, and optoelectronic devices.