Anisotropic violation of the Wiedemann-Franz law at a quantum critical point
Related Experiment Video
Updated: Jun 25, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 16, 2013
Makariy A Tanatar1, Johnpierre Paglione, Cedomir Petrovic
1Département de Physique et RQMP, Université de Sherbrooke, Sherbrooke, Canada.
Abstract:
A quantum critical point transforms the behavior of electrons so strongly that new phases of matter can emerge. The interactions at play are known to fall outside the scope of the standard model of metals, but a fundamental question remains: Is the basic concept of a quasiparticle-a fermion with renormalized mass-still valid in such systems? The Wiedemann-Franz law, which states that the ratio of heat and charge conductivities in a metal is a universal constant in the limit of zero temperature, is a robust consequence of Fermi-Dirac statistics. We report a violation of this law in the heavy-fermion metal CeCoIn5 when tuned to its quantum critical point, depending on the direction of electron motion relative to the crystal lattice, which points to an anisotropic destruction of the Fermi surface.
Related Concept Videos
The de Broglie Wavelength
The Uncertainty Principle
Phase Transitions: Melting and Freezing
Atomic Nuclei: Nuclear Spin State Population Distribution
Second Uniqueness Theorem
In contrast, consider that the electric field is non-unique and apply Gauss's law in divergence form in the region between the conductors and the integral form to the surface...
Deviation from Ideal Behaviour

