Large morphological sensitivity of the magnetothermopower in Co/Cu multilayered systems

TL;DR

This study uses first-principles calculations to explore how the morphology of Co/Cu multilayers affects their magnetothermopower, revealing significant sensitivity linked to quantum well states in thin Co layers.

Contribution

It provides a systematic analysis of the impact of multilayer morphology on thermoelectric properties, highlighting the role of quantum well states in magnetothermopower variations.

Findings

Seebeck coefficient and MTP converge quickly with Co repeats.

Strong variations in thermopower with Co layer thickness.

Quantum well states cause large amplitude and sign changes.

Abstract

We present results of first-principles calculations on the transport properties, both under an electric field or a temperature gradient, in the Co/Cu multilayered systems. The various effects brought about by the changes in the morphological parameters, such as the number of repeats and the layer thickness, are discussed in a systematic way. Our calculations show that the Seebeck coefficient and the magnetothermopower (MTP) converge rather rapidly with the number of Co repeats. In the range of thin Co layers, we find strong variations in amplitude and sign of both the Seebeck coefficient and the MTP. These large variations, which have no correspondent in the (magneto)conductance, are shown to be the result of quantum well states present in the minority spin channel of thin Co layers.