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

摘要

New advances in x-ray diffraction, extended x-ray absorption fine structureEXAFS and x-ray absorption near edge structure XANES using synchrotronradiation have now provided compelling evidence for a short range chargedensity wave phase (CDW) called striped phase in the CuO2 plane of all cupratehigh temperature superconductors. The CDW is associated with a bond order wave(BOW) and an orbital density wave (ODW) forming nanoscale puddles which coexistwith superconducting puddles below Tc. The electronic CDW crystalline phaseoccurs 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 ofanisotropic extended objects proposed for supercooled water is used to describe: a) the underdoped regime as a first spinodal regime of a slightly dopedcharge transfer Mott insulator puddles coexisting with the striped polaronicCDW puddles; and b) the optimum doping regime as a second spinodal regime wherestriped polaronic CDW puddles coexist with the normal 2D metal puddles. Thiscomplex phase separation with 3 competing phases depends on the strength of theanisotropic electron-phonon interaction that favors the formation stripedpolaronic CDW phase.