Study of electronic, magneto-optical and transport properties of double perovskite Ca2XMnO6 (X = Ti, Cr) under uniaxial compressive strain by using a DFT method

Abstract

Under the effect of uniaxial compressive strain along [001]-direction, the electronic, magneto-optical, and electronic transport properties of double perovskite oxide were realized by substituting the Ti atom by Cr atom in Ca2TiMnO6 (CTMO). A first-principles method within the various approximations (PBEsol-GGA, GGA+U, YS-PBE0 and TB-mBJ) has been employed. The analysis of the electronic structure reveals that the compound Ca2CrMnO6 (CCMO) has a half-metallic (HM) ferromagnet (FM) nature which attributes to hybridization between Cr-3[Formula: see text], Mn-3[Formula: see text] and O-2[Formula: see text] states. CTMO exhibits an integer value of magnetic moment 3 [Formula: see text]. However, CCMO exhibits the half-metallicity (HM) under compressive strain from −2% to −5% with the total magnetic moment, a value of 5 [Formula: see text]. CCMO possesses a mediocre spin-down bandgap ([Formula: see text]2 eV) optimum for thermoelectricity and optoelectronics. The optical properties within GGA+U reveal that the CCMO can absorb light under all frequencies. We have calculated the Seebeck coefficient, and electrical and electronic thermal conductivities to determine the thermoelectric (TE) figure of merit (ZT), which is found to be approaching 1 at room temperature considering the spin-down electrons. This compound CCMO may be used for optoelectronic, solar cell, and TE applications due to its amazing properties.