Electron structure and phonon dynamics of LiNbRhAl quaternary Heusler compound

Abstract

Li based quaternary Heusler compounds, having 18 valence electrons show significant applications in different fields i.e., spintronics, thermoelectric and photo voltaic etc. We report the structural stability, electronic property and dynamical stability of LiNbRhAl compound, (Li based QH alloy) via volume optimization and phonon dynamics. Calculations have been performed using Generalized Gradient Approximation based on Density Functional Theory. LiNbRhAl compound crystallizes in LiMgPdSn – type crystal structure having three types of atomic arrangements. We found atomic arrangement of type-3 is energetically most stable. Self-consistence band structure calculations show that valence band (VB) lie from – 4 eV to the Fermi level (EF), whereas conduction band (CB) span up to 2 eV above the EF. Our DOS plots show that Rh-4d states mainly contribute in valence band (VB), while Nb-4d states dominate in both VB and CB bands near EF and open an indirect band gap of 0.177 eV. Presence of positive frequencies in phonon dispersion curve shows that the above-mentioned compound is dynamically stable.