A Spin-Polaron Technique Utilized on Triangular-Lattice Antiferromagnet
  By expressing the Holstein-Primakoff transformation in a symmetric form a modified spin-polaron technique utilized on triangular-lattice antiferromagnet is developed. With the technique, we have treated an extended t-J model, calculated the quasiparticle dispersion, and we also compared the the dispersion with that obtained by other method. 
Z. H. Dong