Properties and detection of spin nematic order in strongly correlated electron systems

A spin nematic is a state which breaks spin SU(2) symmetry while preserving translational and time reversal symmetries. Spin nematic order can arise naturally from charge fluctuations of a spin stripe state. Focusing on the possible existence of such a state in strongly correlated electron systems, we build a nematic wave function starting from a t-J-type model. The nematic is a spin-2 operator, and therefore does not couple directly to neutrons. However, we show that neutron scattering and Knight-shift experiments can detect the spin anisotropy of electrons moving in a nematic background. We find the mean-field phase diagram for the nematic taking into account spin–orbit effects.