arXiv:cond-mat/0404206 · Physical Review B
d -wave pairing in lightly doped Mott insulators
Evgeny A. Plekhanov, Federico Becca, Sandro Sorella
Abstract
We define a suitable quantity ${Z}_{c}$ that measures the pairing strength of two electrons added to the ground-state wave function by means of the anomalous part of the one-particle Green's function. ${Z}_{c}$ discriminates between systems described by one-electron states, like ordinary metals and band insulators, for which ${Z}_{c}=0$, and systems where the single particle picture does not hold, like superconductors and resonating valence bond insulators, for which ${Z}_{c}\ensuremath{\ne}0$. By using a quantum Monte Carlo projection technique for the Hubbard model at $U∕t=4$, a finite ${Z}_{c}$, with $d$-wave symmetry, is found at half filling and in the lightly doped regime, thus emphasizing a qualitatively new feature coming from electronic correlation.