Structure stability, half metallic ferromagnetism, magneto-electronic and thermoelectric properties of new zintl XCr2Bi2 (X=Ca, Sr) compounds for spintronic and renewable energy applications

Abstract

Employing full-potential linearized augmented plane waves (FP-LAPW) methods, the structural stability, electronic nature, magnetic and thermoelectric properties of XCr2Bi2 (X = Ca, Sr) were theoretically investigated for the first time. The structure stability of these materials was confirmed by formation energy and cohesive energy. Based on its electronic properties, the energy band gaps were decreased from 1.55 eV to 1.53 eV and from 1.93 eV to 1.6 eV for CaCr2Bi2 and SrCr2Bi2 respectively in the spin down channel in the valence band regime, when we used GGA + U instead of PBE-GGA approximation. The calculated magnetic optimization and larger magnetic moments shows strong ferromagnetism in these compounds. The computed partial density of states (PDOS) plots predicts that the bonding is mainly achieved due to hybridization of Cr-d with Bi-p states. Using Boltztrap code we have calculated the variation of thermoelectric properties of these compounds that is electrical conductivity (σ/τ), Seebeck coefficient (S), electronic thermal conductivity (k/τ) and essentially Power factor (PF) in both spin channels.