Thermoelectric and thermospin transport in a ballistic junction of graphene

TL;DR

This paper theoretically investigates thermoelectric and spin transport in a graphene ribbon with Rashba spin-orbit coupling, revealing how temperature gradients induce charge, spin currents, and heat transfer in a ballistic regime.

Contribution

It introduces a comprehensive theoretical analysis of thermospin effects in graphene with Rashba coupling, including spin Nernst effect and heat currents, under ballistic transport conditions.

Findings

Thermally induced charge current and Seebeck voltage in graphene.

Presence of spin Nernst effect with perpendicular spin currents.

Heat current transfer due to electron flow between reservoirs.

Abstract

We consider theoretically a wide graphene ribbon, that on both ends is attached to electronic reservoirs which generally have different temperatures. The graphene ribbon is assumed to be deposited on a substrate, that leads to a spin-orbit coupling of Rashba type. We calculate the thermally induced charge current in the ballistic transport regime as well as the thermoelectric voltage (Seebeck effect). Apart from this, we also consider thermally induced spin current and spin polarization of the graphene ribbon. The spin currents are shown to have generally two components; one parallel to the temperature gradient and the other one perpendicular to this gradient. The latter corresponds to the spin current due to the spin Nernst effect. Additionally, we also consider the heat current between the reservoirs due to transfer of electrons.