Competing orders in the phase diagram of cuprate superconductors

Abstract

Abstract.We perform self-consistent calculations in the framework of the Bogoliubov-deGennes theory with a model Hubbard Hamiltonian with strong local correlations. The calculations are performed in a charge density disordered system to study the competition of charge inhomogeneity, spin disorder and superconductivity These calculations are appropriate to describe the cuprate superconductors' phase diagram with the competition of different phases. We find that, in the presence of charge disorder the spin density wave (SDW) order occurs at higher temperatures above the opening of the superconducting gap. This is in opposition to the homogeneous systems where the SDW phase appears in the low doping compounds in the superconducting phase. These finding provides an explanation to the non-Fermi liquid behavior of the cuprates normal phase. IntroductionThe origin of the superconducting gap associated with the superconducting state and the relation to the pseudogap above the transition temperature (T c ) remains one of the central questions in high-T c research [1,2]. The normal phase properties differs completely from the BCS superconductors. It is a matter of intense debate whether this problem is connected with the charge inhomogeneities observed in many different experiments [3,4,5,6,7,8,9,10].In order to obtain a unified interpretation to all of these observations we studied an electronic phase separation (EPS) transition that generates regions of low and high densities. Such a transition may be driven by the lower free energy of undoped antiferromagnetic (AF) regions[11] (intrinsic) or by the out of plane dopants[12] (extrinsic origin).In this context we perform the study of the the superconducting (SC) and antiferromagnetic (AF) order in a model t-t'-U-V Hamiltonian commonly used to describe the cuprates [13,14] in an electronic disordered system. Chen and Ting [14] have studied this model for different doping and temperature and found that the AF is stronger at low doping and high temperatures. Self-consistent calculations in the Bogoliubov-deGennes (BdG) framework indicates that the AF order persists above the opening of the SC order parameter at very high temperatures. This is used to interpret the normal pseudogap phase, since this type of spin density wave will cause an additional scattering to the electrons and will change the Fermi liquid properties.

Uncovering anisotropic magnetic phases via fast dimensionality analysis

“…1 Layered oxides, chalcogenides, and pnictides based on iron and copper have two-dimensional square planar lattices of spins that can be doped to produce complex phase diagrams including high-temperature superconductivity. [2][3][4][5] It is a major goal of materials science to find new materials with these motifs, compare interactions in compounds comprised of similar motifs, and to find new magnetic motifs that have yet-unknown properties.…”