Intermediate-Coupling Theory for the Spectral Weight of Spin Polaron
Abstract
Description
Within the intermediate-coupling theory, the quasiparticle weight $Z$ of one hole injected in the undoped antiferromagnetic ground state is studied. We find that, for the hole located at the quasiparticle band minimun with momentum ${\bf k}_0 = (\pm \fracπ{2}, \pm \fracπ{2})$, $Z$ is finite. By comparing the results obtained by the self-consistent Born approximation, we show that the intermediate-coupling theory for $Z$ is appropriate only when $J/t \stackrel{>}{\sim} 1.6$. Finally, the reason why this approach fails in the small-$J$ case will also be clarified.
4 pages, RevTeX, 2 PS figures
4 pages, RevTeX, 2 PS figures