Ginzburg-Landau Like Theory for High Temperature Superconductivity in the Cuprates: Emergent d-wave Order

TL;DR

This paper introduces a Ginzburg-Landau inspired phenomenological theory for high-temperature superconductivity in cuprates, modeling the complex order parameter with a spin singlet bond amplitude and predicting properties consistent with experiments.

Contribution

It proposes a novel functional based on bond pair amplitudes with a positive interaction leading to d-wave order, providing a unified explanation for various experimental observations.

Findings

Accurately predicts T* and T_c as functions of doping

Matches superfluid stiffness and specific heat measurements

Explains ARPES features like Fermi arcs and gap bending

Abstract

High temperature superconductivity in the cuprates remains one of the most widely investigated, constantly surprising, and poorly understood phenomena in physics. Here, we describe briefly a new phenomenological theory inspired by the celebrated description of superconductivity due to Ginzburg and Landau and believed to describe its essence. This posits a free energy functional for the superconductor in terms of a complex order parameter characterizing it. We propose, for superconducting cuprates, a similar functional of the complex, in plane, nearest neighbor spin singlet bond (or Cooper) pair amplitude psi_ij. A crucial part of it is a (short range) positive interaction between nearest neighbor bond pairs, of strength J'. Such an interaction leads to nonzero long wavelength phase stiffness or superconductive long range order, with the observed d-wave symmetry, below a temperature T_c\simzJ' where z is the number of nearest neighbours; it is thus an emergent, collective consequence. Using the functional, we calculate a large range of properties, e.g. the pseudogap transition temperature T* as a function of hole doping x, the transition curve T_c(x), the superfluid stiffness rho_s(x,T), the specific heat (without and with a magnetic field) due to the fluctuating pair degrees of freedom, and the zero temperature vortex structure. We find remarkable agreement with experiment. We also calculate the self energy of electrons hopping on the square cuprate lattice and coupled to electrons of nearly opposite momenta via inevitable long wavelength Cooper pair fluctuations formed of these electrons. The ensuing results for electron spectral density are successfully compared with recent ARPES experiments, and comprehensively explain strange features such as temperature dependent Fermi arcs above T_c and the 'bending' of the superconducting gap below T_c .