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arXiv · 2002.01914

Topological spin torque emerging in classical-spin systems with different time scales

Michael Elbracht·Simon Michel·Michael Potthoff
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Abstract

In classical spin systems with two largely different inherent time scales, the configuration of the fast spins almost instantaneously follows the slow-spin dynamics. We develop the emergent effective theory for the slow-spin degrees of freedom and demonstrate that this generally includes a topological spin torque. This torque gives rise to anomalous real-time dynamics. It derives from the holonomic constraints defining the fast-spin configuration space and is given in terms of a topological charge density which becomes a quantized homotopy invariant when integrated.

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Michael Elbracht, Simon Michel, Michael Potthoff. 2020-02-05. Topological spin torque emerging in classical-spin systems with different time scales. https://doi.org/10.1103/physrevlett.124.197202

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