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 $\eta$ 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 $\eta$ parameter for enhancing SC.

• Received 19 June 2008

DOI:https://doi.org/10.1103/PhysRevLett.102.027002