Interplay among critical temperature, hole content, and pressure in the cuprate superconductors

TL;DR

This paper models the critical temperature in cuprate superconductors using an extended Hubbard model, revealing how T_c depends on hole content and pressure, aligning with experimental observations and estimating coupling strength variations.

Contribution

It introduces a pressure-dependent extended Hubbard model to explain the non-monotonic T_c behavior and separates intrinsic effects from carrier concentration influences.

Findings

T_c exhibits non-monotonic dependence on hole content.

Pressure affects T_c through both intrinsic and carrier concentration effects.

Estimated how inter-site coupling varies with lattice scale.

Abstract

Within a BCS-type mean-field approach to the extended Hubbard model, a nontrivial dependence of T_c on the hole content per unit CuO_2 is recovered, in good agreement with the celebrated non-monotonic universal behaviour at normal pressure. Evaluation of T_c at higher pressures is then made possible by the introduction of an explicit dependence of the tight-binding band and of the carrier concentration on pressure P. Comparison with the known experimental data for underdoped Bi2212 allows to single out an `intrinsic' contribution to d T_c / d P from that due to the carrier concentration, and provides a remarkable estimate of the dependence of the inter-site coupling strength on the lattice scale.