Structural stabilities, electronic and elastic properties for LaSb: A first-principles study

We theoretically study the pressure induced solid-solid phase transitions, electronic and elastic properties of LaSb by using first-principles calculations based on density functional theory (DFT), in the presence and in the absence of spin-orbit coupling (SOC). The calculations indicate that there exists a structural phase transition from NaCl-type (B1) structure to body centered tetragonal (BCT) structure at the transition pressure (pt) of 13.73 GPa (without SOC) and 13.84 GPa (with SOC). The origin of the SOC having a minor effect on obtaining pt was analyzed. The chemical bond between La and Sb is mainly ionic. The calculated band structures indicate that B1 and BCT phases of LaSb are metallic. A pseudogap appears around the Fermi level of the total density of states (DOS) of B1-LaSb, which may contribute to its stability. The calculated elastic constants are well consistent with the experimental values.