Dynamical spin response of electron doped Mott insulators on a triangular lattice

The spin dynamics of electron doped Mott insulators on a triangular lattice is studied based on the t – J model. It is found that the particularly universal behaviors of integrated dynamical spin structure factor seen in the doped Mott insulators on a square lattice, are absent in the doped Mott insulators on a triangular lattice, indicating the presence of the normal state gap. As a result, the spin–lattice relaxation rate 1 / T 1 divided by T reduces with decreasing temperatures in the temperature region above 0.2 J ≈ 50 K , then follows a Curie–Weiss-like behavior at the temperature less than 50 K, in qualitative agreement with experimental observations.