Stratonovich-Ito integration scheme in ultrafast spin caloritronics

TL;DR

This paper introduces a new theoretical approach using supersymmetric stochastic theory and Ito-Stratonovich integration to analyze the ultrafast formation of the spin Seebeck current, revealing transient components and rapid decay dynamics.

Contribution

It presents a novel time-resolved theoretical framework for the spin Seebeck effect using supersymmetric stochastic methods and Ito-Stratonovich calculus.

Findings

Early spin Seebeck current has nonzero transversal and longitudinal components.

Transversal components decay via dephasing over the dipole-dipole reservoir.

Decay process occurs on sub-nanosecond timescales, enabling ultrafast control.

Abstract

The magnonic spin Seebeck effect is a key element of spin caloritronic, a field that exploits thermal effects for spintronic applications. Early studies were focused on investigating the steady-state nonequilibrium magnonic spin Seebeck current, and the underlying physics of the magnonic spin Seebeck effect is now relatively well established. However, the initial steps of the formation of the spin Seebeck current are in the scope of recent interest. To address this dynamical aspect theoretically we propose here a new approach to the time-resolved spin Seebeck effect. Our method exploits the supersymmetric theory of stochastics and Ito - Stratonovich integration scheme. We found that in the early step the spin Seebeck current has both nonzero transversal and longitudinal components. As the magnetization dynamics approaches the steady-state, the transversal components decay through dephasing over the dipole-dipole reservoir. The time scale for this process is typically in the sub-nanoseconds pointing thus to the potential of an ultrafast control of the dynamical spin Seebeck during its buildup.