An Ab-initio Study of Structural, Elastic, Electronic, Vibrational and Optical Properties of Semiconductor NaAlSi Compound for Optoelectronic Applications


Çiftci Y.

in: Advances in Optoelectronic Materials, Shadia Ikmayies,Hatice Hilal Kurt, Editor, Springer, London/Berlin , Geneve, pp.125-144, 2021

  • Publication Type: Book Chapter / Chapter Research Book
  • Publication Date: 2021
  • Publisher: Springer, London/Berlin 
  • City: Geneve
  • Page Numbers: pp.125-144
  • Editors: Shadia Ikmayies,Hatice Hilal Kurt, Editor
  • Gazi University Affiliated: Yes

Abstract

Semiconducting ternary half-Heusler (HH) compounds with narrow band gaps have turned out to be an important class of materials in recent years due to their wide range of interesting physical properties (eg, high melting point, large thermal conductivity, large thermopower and unusual magnetic properties, etc.). Compounds formed in the half-Heusler structure have proven to be an important class of materials in recent years. Due to their potential applications in cooling and power generation, high-performance thermoelectric materials have attracted a lot of attention from the science community. They crystallize in MgAgAs structure with the F43m space group. This structure consists of four interpenetrating face-centered cubic (FCC) sublattices where three of them contain one of the three elements each, and the fourth sublattice is vacant. In this study, we focus on structural, electronic, elastic, lattice dynamic and optical properties of NaAlSi using ab-initio densityfunctional theory (DFT) within the generalized gradient approximation (GGA) for the exchange-correlation potential. The calculated lattice constants were in good agreement with the available data. Our band structure calculations show that NaAlSi has an indirect energy band gap of 0.39 eV at and X Brillouin zone. In addition to the electronic structure, elastic and optical properties, phonon dispersion curves and phonon density of states (DOS) were calculated. The elastic constants Cij are calculated using the total energy variation with strain technique. Calculated elastic results show that this compound is mechanically stable. The obtained phonon spectra for NaAlSi do not exhibit any …