First principle calculation of structional and Electronicpropertiesofbifeo3usingquantum Espresso package

Abstract

TheStructural andelectronicProperties of BismuthFerrite(BiFeO3)wasinvestigated with density functional theory (DFT) using Quantum Espresso package. Our study was based on Density Functional Theory (DFT) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, Vanderbilt (Norm-conserving) pseudo po tentials and the plane wavebasissetimplementedintheQuantum-ESPRESSOpack age. The calculation of the total minimum energy and the total minimum force of BiFeO3 wascalculatedasafunctionofcutoffenergyandK-pointssampling. Thetotal minimumenergy per cell is monotonically decreasing with increasing cutoff energy due to variational principle. However, this trend can not be predicted from increas ing the k-points sampling. The energy cut-off (90 Ry) and k-point grid (5x5x5) valued from total minimum energy convergence test. The computational value of the equi librium lattice constant is 10.0 Bohr. This result is nearly in good agreement with experimental value is 10.2569 Bohr, with the experimental result of percentage error of 2.4%. Inadditiontothisthebandstructureandtotaldensityofstatearecalculated. Fromthebandstructure it is observed that the band gap value is under estimated as compared to the experimental band gap value and the band gap of bismuth ferrite (BiFeO3) is 1.68 eV.