Spin-dependent heat signatures of single-molecule spin dynamics

TL;DR

This paper explores how spin dynamics in a single-molecule magnet influence transient heat signatures, revealing control mechanisms via bias, tunneling, and exchange interactions, with implications for spin-dependent thermoelectric applications.

Contribution

It introduces a model combining nonequilibrium Green's functions and spin dynamics to analyze spin-dependent heat currents in single-molecule magnets under time-dependent voltages.

Findings

Heat current has charge and spin contributions related to Peltier effects.

Spin dynamics produce identifiable signatures in heat transfer.

Bias voltage can reverse net heat transfer due to local Zeeman splitting.

Abstract

We investigate transient spin-dependent thermoelectric signatures in a single-molecule magnet under the effect of a time-dependent voltage pulse. We model the system using nonequilibrium Green's functions and a generalized spin equation of motion incorporating the dynamic electronic structure of the molecule. We show that the generated heat current in the system is due to both charge and spin contributions, related to the Peltier and the spin-dependent Peltier effect. There is also a clear signature in the heat current due to the spin dynamics of the single-molecule and a possibility to control the spin-dependent heat currents by bias, tunneling coupling and exchange interaction. A reversal of the net heat transfer in the molecule is found for increasing bias voltage due to the local Zeeman split and we can correlate the net heat transfer with the local anisotropies and dynamic exchange fields in the system.