Cooperative Nernst Effect of Multilayer Systems: Parallel Circuit Model Study

TL;DR

This paper presents a circuit model for multilayer systems that reveals a cooperative Nernst effect, showing how thickness tuning can significantly enhance transverse thermoelectric responses in film-substrate setups.

Contribution

It introduces a parallel circuit model to analyze thickness-dependent thermoelectric responses, highlighting the cooperative Nernst effect in multilayer systems.

Findings

Transverse responses peak due to cooperative effects.

Nernst effect in bismuth films can be greatly enhanced.

Thickness ratio tuning optimizes thermoelectric performance.

Abstract

Transverse thermoelectric power generation has emerged as a topic of immense interest in recent years owing to the orthogonal geometry which enables better scalability and fabrication of devices. Here, we investigate the thickness dependence of longitudinal and transverse responses in film-substrate systems i.e., the Seebeck coefficient, Hall coefficient, Nernst coefficient and anomalous Nernst coefficient in a unified and general manner based on the circuit model, which describes the system as the parallel setup. By solving the parallel circuit model, we show that the transverse responses exhibit a significant peak, indicating the importance of a cooperative effect between the film and the substrate, arising from circulating currents that occur in these multilayer systems in the presence of a temperature gradient. Finally, on the basis of realistic material parameters, we predict that the Nernst effect in bismuth thin films on doped silicon substrates is boosted to unprecedented values if the thickness ratio is tuned accordingly, motivating experimental validation.