Dissipation engineering non-reciprocal spin-spin interactions via itinerant electrons

While the detailed balance present in equilibrium ensures the action-reaction symmetry of the interparticle interactions, they can be broken once the system is out of equilibrium. Indeed, such non-reciprocal interactions are ubiquitously observed in various soft active systems, e.g. in chemically or optically active colloidal systems. Recent studies revealed that non-reciprocal interactions may lead to collective phenomena unique to non-equilibrium many-body systems, such as the emergence of non-reciprocal phase transitions [1] and odd elasticity [2]. However, non-reciprocal interactions have not been implemented in electronic systems. In this talk, inspired by the recent advance in soft matter physics, we theoretically propose a way to engineer non-reciprocal interactions between the localized spins in a magnetic metal by driving the system out of equilibrium. We show that the itinerant electrons may mediate non-reciprocal spin-spin interaction when a light source that controls the dissipation is appropriately injected. Our work provides a novel tool to engineer non-equilibrium states of matter in electronic systems.





[1] M. Fruchart*, R. Hanai*, P. B. Littlewood, V. Vitelli, Nature 592, 363 (2021).

[2] C. Scheibner, et al., Nat. Phys. 16, 475 (2020).