Pressure-dependent evolution of Bi2Sr2CaCu2O8+δ: DFT insights for high-pressure superconducting applications

In this study, we employ Density functional theory to explore how pressure affects various characteristics of Bi₂Sr₂CaCu₂O₈₊δ (BSCCO-2212) from 0 to 30 GPa. The equilibrium volume and bulk modulus we calculated matched observed data quite closely, which lends credence to the accuracy of our methods. As pressure increased, we observed a consistent decrease in volume, suggesting the material's lattice is remarkably resilient. The mechanical properties, including elastic constants and moduli, improved with increasing pressure and maintained stability based on the Born criteria. Interestingly, elastic anisotropy decreased somewhat, pointing towards a trend of more uniform mechanical behavior. Moreover, thermodynamic assessments showed lattice hardening, as indicated by an increasing Debye temperature, a decreasing Grüneisen parameter, and suppressed thermal expansion. Dynamical stability was confirmed through phonon dispersion calculations, which revealed no imaginary frequencies across the Brillouin zone. The agreement between theoretical and experimental results highlights DFT's ability to predict the behavior of high-Tc cuprates under these conditions. It is plausible that the adjustable properties of BSCCO-2212 could make it useful in high-field magnets, cryogenic electronics, and perhaps even other demanding superconducting contexts.