Spin transport in the bilinear–biquadratic Heisenberg model on square lattice

Abstract

We analyze the spin coefficients in the spin-1 bilinear–biquadratic Heisenberg model (BBQ) using the SU(3) Schwinger boson approach. The calculations were performed for the model in the ferro- and antiferromagnetic phases, where the AC and DC spin conductivities where computed and the effect of the biquadratic coupling Jbq2 and next-nearest neighboring exchange interactions J2 on spin conductivity analyzed. The aim is to verify the influence of phase transition between the different phases of the system on regular part of the spin conductivity σreg(ω) (AC contribution) and Drude’s weight, that represents the DC contribution. We get that the highest peaks in the spin conductivity in the ferro- and antiferromagnetic phases of the model depends strongly on the values of the exchange coupling constants J2 and Jbq2, as expected.