Electronic Phase Separation Transition as the Origin of the Superconductivity and the Pseudogap Phase of Cuprates

TL;DR

This paper introduces an electronic phase separation transition as the fundamental origin of both the pseudogap and superconducting phases in cuprates, using a Cahn-Hilliard model to explain experimental observations.

Contribution

It proposes a novel phase transition mechanism that accounts for pseudogap and superconductivity in cuprates, linking phase separation with intragrain superconductivity and Josephson coupling.

Findings

The model reproduces scanning tunneling microscopy data.

It explains the emergence of zero resistivity through intergrain Josephson coupling.

The phase separation transition occurs near the upper pseudogap temperature.

Abstract

We propose a new phase of matter, an electronic phase separation transition that starts near the upper pseudogap and segregates the holes into high and low density domains. The Cahn-Hilliard approach is used to follow quantitatively this second order transition. The resulting grain boundary potential confines the charge in domains and favors the development of intragrain superconducting amplitudes. The zero resistivity transition arises only when the intergrain Josephson coupling $E_J$ is of the order of the thermal energy and phase locking among the superconducting grains takes place. We show that this approach explains the pseudogap and superconducting phases in a natural way and reproduces some recent scanning tunneling microscopy data