Pressure induced structural, electronic, optical and thermal properties of CsYbBr 3, a theoretical investigation

摘要

This article presents the variation of structural, electronic, thermal and optical properties of a halide perovskite CsYbBr3with increasing pressure, employing density functional theory. The pressure effect was determined in range of 0–15?GPa. In which stability of CsYbBr3remains valid, as, verified from negative values of enthalpy of formation and phonon dispersion curves. A significant change was observed in lattice constant, bond lengths, bulk modulus and its pressure derivative, volume and ground state energy, with increasing pressure. The calculated electronic properties presented CsYbBr3as a semiconductor with direct band gap of 3.61?eV. However, pressure rise shift the Yb-dstates toward the Fermi level and causes a decrease in band gap. At 12?GPa, CsYbBr3presents the semi metallic nature while further increase in pressure makes it as metallic. Moreover, Debye temperature (Grüneisen parameter) was observed to increase (decrease) with pressure rise while the lattice thermal conductivity was found to increase. The calculated optical properties exposed the suitability of CsYbBr3in pressure tunable opto-electronic devices.