סמינר בחומר מעובה: Spinons spin current in one dimension

The antiferromagnetic Heisenberg spin-1/2 chain is a paradigmatic model in the study of frustrated spin systems known to host fractionalized quasiparticles, termed spinons, carrying spin-1/2 and no charge. The presence of spinons in quasi-1D materials has been unambiguously demonstrated in the past using inelastic neutron scattering as well as other dynamical probes.

In this talk I will present our analysis of the spin current generated at an interface between an antiferromagnetic spin-1/2 chain and a metal in presence of an external magnetic field, as probed in a spin Seebeck effect experiment. I will show that at low temperatures the spin current is controlled by the marginal backscattering interaction between spinons. Varying the microscopic exchange interaction between next-nearest-neighbor spins in this model allows tuning the backscattering interaction between the low energy spinons. At the non-interacting point we find that the spin current vanishes. Our analysis is based on field theoretical arguments and are supported by numerical simulations using matrix-product-state techniques.