Competition between antiferromagnetism and superconductivity, electron-hole doping asymmetry and "Fermi Surface" topology in cuprates

TL;DR

This study uses variational Monte Carlo to explore how Fermi surface topology influences the competition between antiferromagnetism and superconductivity in cuprates, explaining doping asymmetries.

Contribution

It reveals that a single Fermi surface parameter governs the phase diagram features, providing insight into doping asymmetries and suggesting band engineering to enhance superconductivity.

Findings

AF dominates in electron-doped cuprates.

SC is dominant in hole-doped cuprates.

Fermi surface topology controls phase competition.

Abstract

We investigate the asymmetry between electron and hole doping in a 2D Mott insulator, and the resulting competition between antiferromagnetism (AF) and d-wave superconductivity (SC), using variational Monte Carlo for projected wave functions. We find that key features of the T = 0 phase diagram, such as critical doping for SC-AF coexistence and the maximum value of the SC order parameter, are determined by a single parameter which characterises the topology of the "Fermi surface" at half filling defined by the bare tight-binding parameters. Our results give insight into why AF wins for electron doping, while SC is dominant on the hole doped side. We also suggest using band structure engineering to control the parameter for enhancing SC.