Beyond Kelvin's Relation: A Giant Transverse Thomson Response for Efficient Cryogenic Cooling

Area of Science:

• Solid-state physics
• Materials science
• Cryogenic engineering

Background:

• Efficient solid-state cooling at cryogenic temperatures is a significant challenge.
• Current thermoelectric materials and devices are primarily optimized for power generation, not refrigeration.

Purpose of the Study:

• To demonstrate a giant Thomson and transverse Thomson response in a correlated semiconductor.
• To explore the potential of phonon-drag enhanced thermoelectric transport for cryogenic cooling.

Main Methods:

• Investigated the Thomson and transverse Thomson response in FeSb2 below 60 K.
• Utilized strong phonon-drag effects to enhance thermoelectric transport.
• Analyzed the temperature dependence of the Seebeck coefficient and thermopower under magnetic fields.

Main Results:

• Observed a giant longitudinal Thomson coefficient (∼800 μV K⁻¹) due to the pronounced temperature dependence of the Seebeck coefficient.
• Demonstrated a giant transverse Thomson effect (∼29 μV K⁻¹) enhanced by a magnetic field.
• Identified phonon drag as a key mechanism for large Thomson responses.

Conclusions:

• Phonon drag is a scalable design principle for achieving large Thomson responses.
• The study suggests a framework for discovering new cryogenic cooling materials with strong phonon-electron coupling.
• The Thomson effect presents a promising route for developing efficient solid-state cooling for quantum technologies.