Dynamics of Holes in Antiferromagnetic State

抄録

Dynamics of holes in the antiferromagnetic state on the square lattice is studied. The dispersion curves, density of states and eigenfunctions of holes are calculated by using the t-J and t-t′-J models. It is found that the hole moves in the antiferromagnetic state being accompanied by spin distortion around it. The dispersion curves consist of almost continuous band and the low energy band splitting from it. The low energy band is caused by a motion of holes mediated by the quantum spin fluctuations and is rather sensitive to the sign and magnitude of the second near-neighbor hopping integral t′. The spectra of the optical conductivity and the Raman scattering due to two spin excitations around holes are calculated and compared with the experimental results. It is shown that spectra in the mid-infrared region appear in both the optical conductivity and Raman scattering.