Researchers at Ludwig-Maximilian University of Munich, Rutgers University, and Seoul National University have proposed a new mechanism that could underpin the unusual properties of strange metal state of matter. The team, led by Andreas Gleis, used a theoretical framework describing heavy fermion materials to study the dynamical scaling associated with the Kondo-breakdown quantum critical point.
This critical point marks the transition between different electronic phases at absolute zero temperatures and is often accompanied by exotic physical properties. The researchers found that some fluctuations in heavy fermion materials decay at a slow Planckian rate when they are in the quantum critical region, governed by the quantum critical points.
Their study suggests that this slow decay rate is responsible for the unusual optical responses observed in strange metals. In contrast to the widespread “marginal Fermi liquid” hypothesis, which attributes these properties to single-electron dynamics, the researchers’ findings propose a new mechanism rooted in critical short-ranged scattering.
The Kondo-breakdown quantum critical point considered in their study is an intrinsic (disorder-free) strange metal fixed point. Theoretical predictions are aligned with optical conductivity measurements collected as part of experiments focusing on heavy-fermion compounds YbRh2Si2 and CeCoIn5.
Further research is planned to explore the mechanism, properties of the newly found strange metal, and its implications for phenomena such as unconventional superconductivity.
Source: https://phys.org/news/2025-03-mechanism-underpinning-intrinsic-strange-metal.html