Elastic behavior, pressure-induced doping and superconducting transition temperature of GdBa2Cu3O7−x

Abstract

Doping superconductors are known to vary the superconducting transition temperature depending on the degree of holes or electrons introduced in a system. In this study, we report how pressure-induced hole doping influences the of GdBa2Cu3O7−x superconducting perovskite. The study was carried out in the framework of density functional theory (DFT) using the Quantum espresso code. Ultrasoft pseudopotential with generalized gradient approximation (GGA) functional was used to calculate the ground state energy using the plane waves (PW). The stability criterion was satisfied from the calculated elastic constants. The BCS theory and the Mc Millan’s equation was used to calculate the of the material at different conditions of pressure. The underdoped regime where the holes were less than those at optimal doping was found to be below 20 GPa of doping pressure. Optimal doping where the material achieved the highest (max) ∼ 20 GPa of the doping pressure. Beyond the pressure of ∼20 GPa was the over doping regime where a decrease in was recorded. The highest calculated (max) was ∼141.16 K. The results suggest that pressure of ∼20 GPa gave rise to the highest in the study.