Effect of Pr-filling in binary skutterudites CoX3 (P, As and Sb) on structural, electronic, elastic and transport properties

Abstract

ABSTRACTWe have studied the effect on the structural, electronic, elastic and transport properties of binary skutterudite CoX3 (X = P, As, Sb) after filling void spaces by Pr atoms. All the calculations are carried out using the full-potential linearised augmented plane wave (FP-LAPW) method within the generalised gradient approximation (GGA) viz, PBE, and PBEsol. In case of binary skutterudites, equilibrium lattice parameters obtained using PBEsol functional are in good agreement with the theoretical and experimental results. The Hubbard parameter (U) has been used with PBEsol-GGA functional to see its effect on the band structures of binary and ternary compounds. Filling of Pr atoms at void positions in binary skutterudites creates the gap between the valence and conduction band. The obtained values of the elastic constants show that CoX3, PrCo4X12 (X = P, As, Sb) are mechanically stable and brittle. Mechanically, PrCo4P12 and PrCo4As12 are anisotropic, but PrCo4Sb12 is isotropic. Obtained saturated Seeback coefficients are approximate −60 μV/K (PrCo4P12), −80 μV/K (PrCo4As12) and −68 μV/K (PrCo4Sb12) in the spin-up channel while in the spin-down channel corresponding values are −10, −50 and −120 μV/K at 800 K, respectively. These values are higher in magnitude than that in the corresponding binary compounds.