Abstract:
The aim of the study was to characteris the GdBa2Cu3O7-x perovskite superconductor with
the view knowing the associated properties under different conditions of pressure. The
study applied the computational methods to investigate the structural, electronic and
mechanical, properties of the GdBa2Cu3O7-x perovskite superconductor and determined
how its properties affect the mechanism of superconductivity. With the local the
generalized gradient approximation in the frame work of density functional theory using
the Quantum espresso code, the ground state properties and equation of state were obtained
using the Plane waves. The phenomenon of phase transition studied through pressure
induction. The effect of pressure on the band structure, density of states and the partial
density of state were also assessed. The orbitals that are responsible for metallization and
superconductivity were also computed at varied pressure. The effect holes doping with
pressure was also simulated. The BCS theory and the Mc Millan’s equation were used to
calculate its superconducting transition temperature at different pressure. Doping with
variation of oxygen concentration was done. The phase transition was found to occur at
21.9 GPa. It was found that pressure results to narrowing of the band gap for this material
and eventually the material undergoes metallization. The orbital that become predominant
at the high superconductivity transition temperature below the pressure of phase transition
were; Cu 1d and O 2p from the CuO in the valence band near the Fermi level and the Gd
5p near the Fermi level. The stability criterion was satisfied from the calculated elastic
constants. Calculated elastic properties were used to calculate Debye temperature and the
maximum value was achived at ~20GP. The underdoped regime, where the holes were
smaller compared to the ones at optimum doping, was determined to be below 20 GPa of
doping pressure. Optimal doping pressure where was achieved at ~ 20 GPa.. There was a
drop in T_C above the pressure of around ~20 GPa, which was considered the overdoping
regime. The highest calculated 𝑇𝐶 (max) was ~141.16 K at ~20GPa. With oxygen doping
the 𝑇𝐶 (max) was found to be 137.9 K when the value of x was 0.65. the finding of the
study can be used to in material design for application
