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ARTICLE

Structural, electronic and thermoelectric properties of LiAlX₂ (X=S and Se) chalcopyrites: promising for thermoelectric power generators

J. Kumari^a, C. Singh^b, R. Agrawal^c, B. L. Choudhary^a, A. S. Verma^d,e,*

a Department of Physics, Banasthali Vidyapith, Rajasthan, India, 304022
b Department of Physics, Agra College, Agra, India, 282002
c Department of Computer Engineering and Applications, G. L. A. University, Mathura, India, 281406
d Division of Research & Innovation, School of Applied and Life Sciences, Uttaranchal University, Uttarakhand, Dehradun – 248007, India
e University Centre for Research & Development, Department of Physics, Chandigarh University, Mohali, Punjab – 140413, India

* Corresponding Author:

Chalcogenide Letters 2023, 20(1), 73-83. https://doi.org/10.15251/CL.2023.201.73

Received 08 October 2022; Accepted 08 January 2023;

Abstract

Herein, we have inquired the structural, electronic and thermoelectric properties of the couple of chalcopyrite structured solids LiAlX₂ (X=S and Se) with the help of density functional theory (DFT), which is tracked by resolution of the Boltzmann transport equation with the constant relaxation time calculations. The LDA (Localized Density Approximation), PBE (Perdew-Burke-Ernzerhof), PBEsol (PBE functional revised for solids) and WC (Wu-Cohen) exchange correlation potentials have been used. The calculated lattice constants a = 5.271 Å; c = 10.178 Å and a = 6.226 Å; c = 12.165 Å for LiAlS₂ and LiAlSe₂ respectively and the band gap of the mentioned compounds are found in range from 1.74 eV to 3.13 eV. The dependency of thermoelectric parameters are calculated with different temperature (300-800K) and carrier concentration 10¹⁸ 10¹⁹ cm^-3 . From the study of ZT (figure of merit’s ZT= S² σT/κ the dimensionless parameter) and it is found that it’s value for both the compounds in n-type as well as in p-type region is ‘unity’. Since these compounds can be the promising candidate for thermoelectric devices also these compounds are non-toxic, eco-friendly and good alternative for the green and renewable source of electric power generators.

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Keywords

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