Universal Properties of Cuprate Superconductors: Tc Phase Diagram, Room-Temperature Thermopower, Neutron Spin Resonance, and STM Incommensurability Explained in Terms of Chiral Plaquette Pairing

TL;DR

This paper demonstrates that four key properties of cuprate superconductors can be explained by a simple counting of four-site plaquettes, linking inhomogeneity and percolation to their superconducting behavior.

Contribution

It introduces a geometric counting rule based on four-site plaquettes that explains multiple cuprate properties without adjustable parameters, highlighting the role of inhomogeneity and percolation.

Findings

Universal Tc phase diagram explained by plaquette counting

Neutron spin resonance peak explained without adjustable parameters

Incommensurability in STM conductance explained by plaquette percolation

Abstract

We report that four properties of cuprates and their evolution with doping are consequences of simply counting four-site plaquettes arising from doping: (1) the universal Tc phase diagram (superconductivity between \approx0.05 and \approx0.27 doping per CuO2 plane, and optimal Tc at \approx0.16), (2) the universal doping dependence of the room-temperature thermopower, (3) the superconducting neutron spin resonance peak (the "41 meV peak"), and (4) the dispersionless scanning tunneling conductance incommensurability. Properties (1), (3), and (4) are explained with no adjustable parameters, and (2) is explained with exactly one. The successful quantitative interpretation of four very distinct aspects of cuprate phenomenology by a simple counting rule provides strong evidence for four-site plaquette percolation in these materials. This suggests that inhomogeneity, percolation, and plaquettes play an essential role in cuprates. This geometric analysis may provide a useful guide to search for new compositions and structures with improved superconducting properties.