Electrically tunable giant Nernst effect in two-dimensional van der Waals heterostructures

TL;DR

This paper demonstrates a large, electrically tunable Nernst effect in graphene/indium selenide heterostructures, with record-high Nernst coefficients at low temperatures, offering new opportunities for thermoelectric and quantum applications.

Contribution

It introduces a novel heterostructure platform with electrical tunability and record Nernst coefficients, advancing low-temperature thermoelectric research.

Findings

Achieved an on/off ratio of 10^3 for the Nernst effect.

Observed a record-high Nernst coefficient of 66.4 μV/K·T at low temperatures.

Demonstrated enhanced photo-Nernst response in the heterostructure.

Abstract

The Nernst effect, a transverse thermoelectric phenomenon, has attracted significant attention for its potential in energy conversion, thermoelectrics, and spintronics. However, achieving high performance and versatility at low temperatures remains elusive. Here, we demonstrate a large and electrically tunable Nernst effect by combining graphene's electrical properties with indium selenide's semiconducting nature in a field-effect geometry. Our results establish a novel platform for exploring and manipulating this thermoelectric effect, showcasing the first electrical tunability with an on/off ratio of 10^3. Moreover, photocurrent measurements reveal a stronger photo-Nernst signal in the Gr/InSe heterostructure compared to individual components. Remarkably, we observe a record-high Nernst coefficient of 66.4 {\mu}V K^(-1) T^(-1) at ultra-low temperatures and low magnetic fields, paving the way toward applications in quantum information and low-temperature emergent phenomena.