Understanding the impact of Y2+ (Y[dbnd]Mn, Fe, and Co) cations on physical properties of SrYGe2O6 clinopyroxene: A DFT insight

Abstract

Pyroxenes are one of the most important minerals in igneous rock with extremely varied compositions. Here, the structural, mechanical, magnetic, thermodynamic, and optoelectronic features of the SrYGe2O6 (Y= Mn, Fe, and Co) in the monoclinic phase is presented by the density functional theory (DFT) investigation. The generated structures using GGA-PBE, GGA-PBSOL, and LDA exchange-correlation functional in a ferromagnetic ordering have lattice parameters that agree with the existing experimental data. All of the three structures are found mechanically stable by Born stability criteria. The most ductile material is SrCoGe2O6, whereas Poisson's ratio (σ) predicts that SrMnGe2O6 is brittle. These have metallic nature for one spin state and semiconducting for another spin state, which confirms the half-metallic or half semiconducting nature. The direct type half-metallic gap for SrCoGe2O6, SrMnGe2O6 and SrFeGe2O6 are found as 1.76 eV, 1.252 eV, and 0.701 eV, respectively. A deep electronic structural configuration is analyzed by the bond population analysis. Effective masses of charge carriers and exciton binding energies revealed insight into the transport properties. The structures exhibit significant UV photon absorption, high visible photon reflectivity, and plasmon peaks of about 13 eV were seen in estimated loss function spectra. These characteristics collectively point to possible applications for these pyroxenes in optoelectronics and spintronics.