Non-classical spin transfer effects in an antiferromagnet

Studies of spin transfer (ST) effects enabling electronic control of the Neel order in antiferromagnet-based (AF) spintronic devices have so far focused on the mechanisms that can be understood within semiclassical approximation for magnetism. However, the ground state of AFs is not a N’eel state, but rather an entangled spin state involving large quantum magnetization fluctuations, which may be expected to result in ST effects not captured by the semi-classical approximation. We utilize tight-binding simulations in a 1D AF modeled as a chain of quantum Heisenberg spins. Among the effects elucidated by the simulations are efficient excitation of multiple fractionalized magnetic excitation (spinon) quanta by a single electron, which is not possible in ferromagnets due to angular momentum conservation, as well as quantum interference of spin wavefunctions, making it possible to induce magnetization dynamics with amplitudes exceeding the transferred magnetic moment. Our results suggest the possibility to utilize non-classical contributions to ST to achieve efficient spin conversion and electronic control of static and dynamical states in AFs.