Spin Dynamics of t-J Model on Triangular Lattice

Abstract

We study the spin dynamics of t-J model on triangular lattice in the Slave-Boson-RPA scheme in light of the newly discovered superconductor Na${}_x$CoO${}_2$. We find resonant peak in the dynamic spin susceptibility in the $d+i{d}^{{}^{\prime }}$-wave superconducting state for both hole and electron doping in large doping range. We find the geometrical frustration inherent of the triangular lattice provide us a unique opportunity to discriminate the SO(5) and RPA-like intepretation of the origin of the resonant peak.

9 pages, 4 figures