Mean-field theory of the chiral spin state.

Abstract

Using the mean-field method, we study some properties of the chiral spin state and give its ground-state wave function under finite doping. We find that as the mass m of the spin fermion increases, the chiral spin state has a Kosterlitz-Thouless-type phase transition, and prove that the chiral spin state in external electromagnetic fields is an incompressible spin liquid with a finite gap which derives from the topological term. As considering the condensation of the hole bosons, we find the chiral spin state goes into a superconducting phase and has two finite gaps.