Influence of interchain coupling on spiral ground-state correlations in frustrated spin-1/2 J1-J2 Heisenberg chains

We investigate the influence of an interchain coupling on the spiral ground-state correlations of a spin-1/2 Heisenberg model consisting of a two- dimensional array of coupled chains with nearest- (J(1)) and frustrating next-nearest-neighbor (J(2)) in-chain exchange couplings. Using the coupled cluster method we calculate the transition point between the commensurate and the incommensurate (spiral) ground states as well as the quantum pitch angle of the spiral ground state. In addition, we provide a simple empirical formula which describes the relation between the quantum pitch angle and the frustration parameter J(2)/J(1).