Variational Monte Carlo study of spin dynamics in underdoped cuprates
Zuodong Yu, Yuan Zhou, Chang-De Gong
The hour-glass-like dispersion of spin excitations is a common feature of underdoped cuprates. It was qualitatively explained by the random-phase approximation based on various ordered states with some phenomenological parameters; however, its origin remains elusive. Here, we present a numerical study of spin dynamics in the $t\text{\ensuremath{-}}J$ model using the variational Monte Carlo method. This parameter-free method satisfies the no double-occupancy constraint of the model and thus provides a better evaluation on the spin dynamics with respect to various mean-field trial states. We conclude that the lower branch of the hour-glass dispersion is a collective mode and the upper branch more than the other candidates is likely the consequence of the stripe state.
arXiv:1711.04479•Physical review. B./Physical review. B•Nov 22, 2017•0 citations