Thermoelectric phenomena in an antiferromagnetic helix: Role of electric field

TL;DR

This paper investigates charge and spin thermoelectric effects in a single-helical antiferromagnetic molecule under electric fields, revealing enhanced spin thermoelectric responses with detailed analysis of various physical parameters.

Contribution

It introduces a comprehensive study of thermoelectric phenomena in antiferromagnetic helices considering both short and long-range hopping, including phononic effects, using non-equilibrium Green's functions.

Findings

Spin thermoelectric response is more favorable than charge response.

Thermoelectric quantities depend strongly on helicity, electric field, and temperature.

Phononic contributions significantly affect thermal conductance.

Abstract

The charge and spin-dependent thermoelectric responses are investigated on a single-helical molecule possessing a collinear antiferromagnetic spin arrangement with zero net magnetization in the presence of a transverse electric field. Both the short and long-range hopping scenarios are considered, which mimic biological systems like single-stranded DNA and $\alpha$-protein molecules. A non-equilibrium Green's function formalism is employed following the Landauer-Buttiker prescription to study the thermoelectric phenomena. The detailed dependence of the basic thermoelectric quantities on helicity, electric field, temperature etc., are elaborated on, and the underlying physics is explained accordingly. The charge and spin \textit{figure of merits} are computed and compared critically. For a more accurate estimation, the phononic contribution towards thermal conductance is also included. The present proposition shows a favorable spin-dependent thermoelectric response compared to the charge counterpart.