Structural And Electronic Properties Of Lina2bi With And Without Considering Spin Orbit Coupling Using Density Functional Theory

Abstract

LiNa2Bi is a bialkali bismuthide that materialize a new state of quantum matter which hosts exotic quantum phenomenon that are basic for fundamental science research and future application. LiNa2Bi is a many electron system and the Schrodinger equa- ¨ tion can not be solved analytically or by simple numerical methods. Calculating the structural and electronic properties of LiNa2Bi from first principles calculations provides access to know all its physical and chemical properties. The first principle calculation based on DFT was employed to investigate the structural and electronic properties of LiNa2Bi using quantum ESPRESSO package. The convergence test of total energy with respect to kinetic energy cutoff and k-point grid of LiNa2Bi was performed consequently to increase the accuracy of computation. Total minimum energy of LiNa2Bi per cell is converged at a cutoff energy of 70 Ry and 6x6x6 k-point grid. The calculated equilibrium lattice constants are a = 5.65 A and ˚ c = 5.4 A while ˚ the experimental values of a and c are 5.639 A and 5.497 ˚ A respectively. With out SOC, ˚ the band gap (indirect) of LiNa2Bi is ∼ 0.18 eV. With SOC, LiNa2Bi became a gap-less system. To get better understanding of the electronic structure, we performed the calculation of DOS and PDOS. Small gap is occurred in DOS of LiNa2Bi. In PDOS of LiNa2Bi, Bi 6p-orbital dominated CB and VB.