Driving Perpendicular Heat Flow: Ambipolar Transverse Thermoelectrics for Microscale and Cryogenic Peltier Cooling

TL;DR

This paper introduces a novel transverse thermoelectric design using band-engineered materials like InAs/GaSb superlattices, enabling efficient heat flow control at microscale and cryogenic temperatures, overcoming limitations of traditional thermoelectrics.

Contribution

The paper presents a new band-engineered transverse thermoelectric concept with orthogonal p- and n-type Seebeck effects, suitable for microscale and cryogenic applications.

Findings

InAs/GaSb superlattices have the appropriate band structure for transverse thermoelectric use.

Transverse thermoelectrics can generate large temperature differences despite low ZT.

The design is advantageous for microscale and cryogenic cooling where traditional thermoelectrics are ineffective.

Abstract

Whereas thermoelectric performance is normally limited by the figure of merit ZT, transverse thermoelectrics can achieve arbitrarily large temperature differences in a single leg even with inferior ZT by being geometrically tapered. We introduce a band-engineered transverse thermoelectric with p-type Seebeck in one direction and n-type orthogonal, resulting in off-diagonal terms that drive heat flow transverse to electrical current. Such materials are advantageous for microscale devices and cryogenic temperatures -- exactly the regimes where standard longitudinal thermoelectrics fail. InAs/GaSb type II superlattices are shown to have the appropriate band structure for use as a transverse thermoelectric.