Competition between antiferromagnetic and superconducting states, electron-hole doping asymmetry, and fermi-surface topology in high temperature superconductors

Abstract

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