Spin Seebeck effect of correlated magnetic molecules

TL;DR

This study explores the spin-dependent thermoelectric properties of correlated magnetic molecules in junctions, revealing how exchange interactions and magnetic anisotropy influence the spin Seebeck effect and thermoelectric efficiency.

Contribution

It provides a detailed analysis of the spin Seebeck effect in correlated magnetic molecules using numerical renormalization group methods, highlighting the impact of magnetic anisotropy and exchange interactions.

Findings

Thermopower depends on exchange interaction strength and magnetic anisotropy.

A significant spin Seebeck effect occurs with easy-plane magnetic anisotropy.

The sign of spin thermopower varies with exchange interaction type and magnitude.

Abstract

In this paper we investigate the spin-resolved thermoelectric properties of strongly correlated molecular junctions in the linear response regime. The magnetic molecule is modeled by a single orbital level to which the molecular core spin is attached by an exchange interaction. Using the numerical renormalization group method we analyze the behavior of the (spin) Seebeck effect, heat conductance and figure of merit for different model parameters of the molecule. We show that the thermopower strongly depends on the strength and type of the exchange interaction as well as the molecule's magnetic anisotropy. When the molecule is coupled to ferromagnetic leads, the thermoelectric properties reveal an interplay between the spin-resolved tunneling processes and intrinsic magnetic properties of the molecule. Moreover, in the case of finite spin accumulation in the leads, the system exhibits the spin Seebeck effect. We demonstrate that a considerable spin Seebeck effect can develop when the molecule exhibits an easy-plane magnetic anisotropy, while the sign of the spin thermopower depends on the type and magnitude of the molecule's exchange interaction.