Fluctuation Relations for Spintronics

TL;DR

This paper derives fluctuation relations in spintronic systems, highlighting how magnetic interactions can violate local balance but still preserve fluctuation symmetries at equilibrium, demonstrated through a quantum dot model.

Contribution

It introduces fluctuation relations for spintronics considering magnetic interactions and shows their validity via a quantum dot example.

Findings

Magnetic interactions can violate local balance conditions.

Fluctuation relations can be derived from micro-reversibility at equilibrium.

Application to a quantum dot coupled to helical edge states confirms the theory.

Abstract

Fluctuation relations are derived in systems where the spin degree of freedom and magnetic interactions play a crucial role. The form of the non-equilibrium fluctuation theorems relies in the assumption of a local balance condition. We demonstrate that in some cases the presence of magnetic interactions violates this condition. Nevertheless, fluctuation relations can be obtained from the micro-reversibility principle sustained only at equilibrium as a symmetry of the cumulant generating function for spin currents. We illustrate the spintronic fluctuation relations for a quantum dot coupled to partially polarized helical edges states.