Fluctuation effects of nonlinear coupling between spin and charge excitations on dynamical correlation functions of the one-dimensional extended Hubbard model
Norikazu Tomita, Keiichirō Nasu
We study fluctuation effects of nonlinear coupling between spin and charge excitations on dynamical correlation functions of the one-dimensional extended Hubbard model at half-filling. Two kinds of dynamical correlation functions, dynamical spin- and charge-correlation functions, are calculated by means of a quantum Monte Carlo simulation. We show that the dynamical spin-correlation function has a new peak on the high-energy side of the well-known magnon peak. Since this peak always appears above the charge-excitation gap, it should originate from a charge fluctuation induced through a final-state interaction of magnon creation. We also show that in the dynamical charge-correlation function, a charge-transfer excitation peak is broadened by fluctuation effects due to magnons. These results clearly show that spin and charge excitations are nonlinearly coupled in this system.
Physical review. B, Condensed matter•Jan 15, 2000•11 citations