Spin drag in a one-dimensional quantum wire

The transport of spin, instead or charge, is the basis of the field of spintronics. Besides in condensed matter, spin transport has recently been explored in experiments with ultracold atoms which allow spin-selective control. A central phenomenon in the transport of spin current is spin drag, where a chemical potential bias on one spin component induces the transport of the other component via interactions. For attractive contact interactions, the ground state of fermions in one dimension is a singlet superfluid, and spin drag is due to pairing of fermions with opposite spin. This was recently observed in a quantum point contact setup [1]. Motivated by recent transport experiments with ultracold atoms [1, 2], we investigate analytically and numerically the possibility of spin drag of repulsively interacting fermions in a one-dimensional wire, where the ground state is a spin density wave.

References

[1] S. Krinner et al., Proc. Natl. Acad. Sci. 113, 8144 (2016)
[2] M. Lebrat et al., Phys. Rev. X 8, 011053 (2018)