Condensation energy, charge ordering and inter-layer coupling in cuprates

TL;DR

This paper investigates how inter-layer Coulomb interactions and charge ordering influence the condensation energy and critical temperature in cuprate superconductors, proposing a potential energy driven mechanism linked to dielectric screening effects.

Contribution

It introduces a charge ordered bilayer model where inter-layer Coulomb energy gain supports pairing, connecting dielectric properties with superconducting energy scales.

Findings

Condensation energy correlates with critical temperature and inter-layer Coulomb energy gain.

Charge ordering patterns are consistent with scanning tunneling microscopy observations.

Calculated dielectric constants align with experimental data across various cuprates.

Abstract

The correlation between the condensation energy and the critical temperature is studied within a charge ordered superlattice bilayer model in which pairing is supported by inter-layer Coulomb energy gain (potential energy driven superconductivity).The 2D pair-condensate can be characterized by a charge ordered state with a "checkerboard" like pattern seen by scanning tunneling microscopy.The drop of the c-axis dielectric screening can be the primary source of the condensation energy at optimal doping.We find that Coulomb energy gain occurs along the c-axis, which is proportional to the measured condensation energy ($U_0$) and to $T_c$: $E_c^{3D} \approx 2 (\xi_{ab}/a_0+1)^2 U_0 \approx k_B T_c$ and is due to inter-layer charge complementarity (charge asymmetry of the boson condensate)where $\xi_{ab}$ is the coherence length of the condensate and $a_0 \approx 3.9 \AA$ is the in-plane lattice c onstant.The static c-axis dielectric constant $\epsilon_c$ is calculated for various cuprates and compared with the available experimental data.