Correlated band structure and the ground-state phase diagram in high-Tc cuprates

TL;DR

This paper reviews a variational cluster approach to study the competition between superconductivity and antiferromagnetism in high-Tc cuprates, successfully reproducing key features of their phase diagram and low-energy excitations.

Contribution

It introduces and validates a variational cluster approach that accurately models the phase diagram and low-energy excitations in high-Tc cuprates, including electron and hole doping effects.

Findings

VCA correctly reproduces low-energy excitations.

Phase diagram includes phase separation and doping-dependent phases.

Enhanced AF robustness in electron-doped cuprates.

Abstract

We review results obtained with a recently proposed variational cluster approach (VCA) for the competition between d-wave superconductivity (dSC) and antiferromagnetism (AF) in the high-Tc cuprates. Comparing the single-particle spectra of a two-dimensional Hubbard model with quantum Monte-Carlo (QMC) and experimental data, we verify that the VCA correctly treats the low-energy excitations. The cluster calculations reproduce the overall ground-state phase diagram of the high-temperature superconductors both for electron- and hole-doping. In particular, they include salient features such as the enhanced robustness of the AF state in case of electron doping. For electron- but also for hole-doping, we clearly identify a tendency to phase separation into a mixed AF-dSC phase at low and a pure dSC-phase at high doping.