Nematic state in an exchange Heisenberg Hamiltonian
Gor'kov L. P. , Sokol A. V.
A qualitative case is made for the possibility of a spin-nematic state in a system of quantum-mechanical spins with a binary exchange interaction causing a frustration. The arguments are based on a possible instability of the spin-wave spectrum in the Neel state with respect to the formation of pairs of quasiparticles.