DFT exploration of pressure dependent physical properties of the recently discovered La3Ni2O7 superconductor

Abstract

The recent discovery of superconductivity in Ruddlesden-Popper bilayer nickelate La3Ni2O7 under pressure has drawn a lot of interest. La3Ni2O7 is isostructural with cuprates in some respect. Investigation of its properties will undoubtedly provide new insights into high-Tc superconductivity. In the present work, we study structural, mechanical, elastic, optoelectronic, thermophysical properties, and Fermi surface topology of La3Ni2O7 under pressure within the range of 30-40 GPa employing the density functional theory (DFT). The calculated structural parameters agree well with the earlier experimental findings. The structural, mechanical, and thermodynamical stability is justified across the entire pressure range. The computed elastic moduli classify the compound as ductile, and the material's ductility is largely unaffected by pressure. The compound has a high level of machinability index and dry lubricity. The electronic band structure reveals metallic feature of La3Ni2O7. The Debye temperature, thermal conductivity, and melting temperature increase with increasing pressure, but in an anomalous manner. The characteristic peaks in refractive index, reflectivity, and photoconductivity exhibit a small shift towards higher energy for all polarizations of the electric field vector with increasing pressure. The investigated material might be a good ultraviolet radiation absorber and can be used as an anti-reflection system. Moreover, the pressure dependent electronic density of states at the Fermi level, pressure induced negligible variations in the repulsive Coulomb pseudopotential, and the changes in the Debye temperature have been used to explore the effect of pressure on the superconducting transition temperature in this study.