Magnetic and Thermoelectric properties of RbCaYF(Y= C and N) Heusler alloys: Promising Candidates for Embedded Systems in Telecommunications

On the basis of density functional theory, the structural, electronic, magnetic and thermoelectric properties of the d0 new quaternary Heusler alloys RbCaYF (Y= C and N) have been analyzed by means of first-principles calculations. The results predict a stable atomic arrangement in Y-type (III) phase with a ferromagnetic order. The two compounds were found to be half-metallic ferromagnets (HMFs) with an integer magnetic moment of 2µB for RbCaCF and 1µB for RbCaNF. The ferromagnetism observed is originated from the polarization of the p-Y orbitals with an sp-hybridization. In addition, RbCaCF and RbCaNF display large half metallic (HM) gaps of 0.879, 0.672 eV using Generalized Gradient Approximation (GGA), and 1.730, 1.934 eV with Generalized Gradient Approximation Modified Becke and Johnson (GGA-mBJ) respectively demonstrating stable half metallic features. Besides, thermoelectric properties were computed over a wide range of temperatures. The two Heusler alloys exhibit high values of electric conductivity and figure of merit especially at high temperatures. RbCaCF and RbCaNF d0 Heusler alloys present high spin polarization, robust half-metallicity and high thermoelectric coefficients, which makes them good candidates for spintronic and thermoelectric applications leading to promising enhancements for embedded systems in telecommunications.