Ground-state properties of the triangular-lattice Heisenberg antiferromagnet with arbitrary spin quantum number $s$

Abstract

We apply the coupled cluster method to high orders of approximation and exact diagonalizations to study the ground-state properties of the triangular-lattice spin-$s$ Heisenberg antiferromagnet. We calculate the fundamental ground-state quantities, namely, the energy $e_0$, the sublattice magnetization $M_{\rm sub}$, the in-plane spin stiffness $\rho_s$ and the in-plane magnetic susceptibility $\chi$ for spin quantum numbers $s=1/2, 1, \ldots, s_{\rm max}$, where $s_{\rm max}=9/2$ for $e_0$ and $M_{\rm sub}$, $s_{\rm max}=4$ for $\rho_s$ and $s_{\rm max}=3$ for $\chi$. We use the data for $s \ge 3/2$ to estimate the leading quantum corrections to the classical values of $e_0$, $M_{\rm sub}$, $\rho_s$, and $\chi$. In addition, we study the magnetization process, the width of the 1/3 plateau as well as the sublattice magnetizations in the plateau state as a function of the spin quantum number $s$.