CDW and similarity of the Mott-Insulator-to-Metal transition in cuprates with the gas to liquid-liquid transition in supercooled water

TL;DR

This paper explores the similarities between the Mott-insulator-to-metal transition in cuprates and the gas to liquid-liquid transition in supercooled water, using advanced x-ray techniques and a Van der Waals model to describe phase coexistence and competition.

Contribution

It introduces a theoretical framework linking cuprate phase transitions with supercooled water behavior through a Van der Waals model of anisotropic objects.

Findings

Evidence for a short-range charge density wave (CDW) in cuprates.

Identification of phase coexistence regimes at different doping levels.

Application of VdW model to describe phase separation in cuprates.

Abstract

New advances in x-ray diffraction, extended x-ray absorption fine structure EXAFS and x-ray absorption near edge structure XANES using synchrotron radiation have now provided compelling evidence for a short range charge density wave phase (CDW) called striped phase in the CuO2 plane of all cuprate high temperature superconductors. The CDW is associated with a bond order wave (BOW) and an orbital density wave (ODW) forming nanoscale puddles which coexist with superconducting puddles below Tc. The electronic CDW crystalline phase occurs around the hole doping 0.125 between the Mott charge transfer insulator, and the 2D metal. The Van der Waals (VdW) theoretical model for a liquid of anisotropic extended objects proposed for supercooled water is used to describe : a) the underdoped regime as a first spinodal regime of a slightly doped charge transfer Mott insulator puddles coexisting with the striped polaronic CDW puddles; and b) the optimum doping regime as a second spinodal regime where striped polaronic CDW puddles coexist with the normal 2D metal puddles. This complex phase separation with 3 competing phases depends on the strength of the anisotropic electron-phonon interaction that favors the formation striped polaronic CDW phase.