Elastic and electro-optical properties of XYZ (X = Li, Na and K; Y = Mg; Z = N, P, As, Sb and Bi) compounds

The physical properties, such as the electronic band structure, elasticity, chemical bonding, and optical properties of XYZ (X = Li, Na and K; Y = Mg and Z = N, S, P, Sb and Bi) compounds are investigated using the Tran-Blaha modified Becke-Johnson's potential. The lattice parameters for these materials increase from N to Bi and vary inversely to the bulk moduli. NaMgBi, NaMgSb, KMgP and KMgBi exhibit ductile behavior, while the remaining materials are brittle in nature. The compounds other than LiMgP, LiMgAs, LiMgSb, NaMgP and NaMgSb exhibit a direct band gap. Hybridization is found between the p-states of N, P, As, Sb and Bi and the p-states of Li, Na and K. Analysis of the charge density plots reveals a mixed covalent and ionic bonding nature. These materials have high optical conductivity and reflectivity in visible and infrared regions of the electromagnetic spectrum, which make them good candidates in many potential applications such as thermoelectrics, spintronics and solar cells. (author)