Anomalously low electronic thermal conductivity in metallic vanadium dioxide

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Physics

Background:

• The Wiedemann-Franz law relates thermal and electrical conductivity in metals.
• Deviations suggest complex electronic behavior, like inelastic scattering or hydrodynamic effects.
• Such deviations are typically observed at very low temperatures.

Purpose of the Study:

• To investigate the Wiedemann-Franz law in metallic vanadium dioxide near its metal-insulator transition.
• To explore the electronic thermal conductivity at high temperatures (240-340 K).
• To understand the underlying mechanisms responsible for observed deviations.

Main Methods:

• Experimental measurements of electrical conductivity.
• Experimental measurements of thermal conductivity.
• Analysis of data in the context of the Wiedemann-Franz law.

Main Results:

• An order-of-magnitude breakdown of the Wiedemann-Franz law was observed.
• This breakdown occurred at high temperatures (240-340 K) in metallic vanadium dioxide.
• The low electronic thermal conductivity suggests the absence of quasiparticles.

Conclusions:

• The study reveals a novel mechanism for Wiedemann-Franz law violation.
• The findings point to a strongly correlated electron fluid where heat and charge diffuse independently.
• This behavior differs from previously known mechanisms and occurs at accessible temperatures.