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Updated: Jun 10, 2026
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Published on: August 2, 2019
Fermi-surface collapse and dynamical scaling near a quantum-critical point
Sven Friedemann1, Niels Oeschler, Steffen Wirth
1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany. Sven.Friedemann@cpfs.mpg.de
Summary
Researchers studied quantum criticality in Ytterbium Rhodium Disilicide (YbRh2Si2) using Hall effect measurements. They discovered that critical fluctuations scale with energy over temperature (E/T), revealing insights into quantum materials and strongly correlated systems.
Area of Science:
- Condensed Matter Physics
- Quantum Materials Science
Background:
- Quantum criticality describes continuous phase transitions in matter at absolute zero temperature.
- Collective fluctuations near quantum-critical points are crucial in quantum materials, but their excitations are poorly understood.
Purpose of the Study:
- To investigate the nature of quantum-critical excitations in the heavy-fermion metal Ytterbium Rhodium Disilicide (YbRh2Si2).
- To understand the role of collective fluctuations in quantum materials and their impact on material properties.
Main Methods:
- In-depth measurements of the Hall effect in YbRh2Si2.
- Isolation of a critical crossover in the Hall coefficient near the quantum-critical point.
- Analysis of the temperature dependence of the critical crossover width.
Main Results:
- A distinct crossover in the isothermal Hall coefficient was observed, linked to the quantum-critical point.
- The width of this critical crossover exhibited a linear dependence on temperature (proportional to T).
- This temperature dependence aligns with energy over temperature (E/T) scaling of quantum-critical fluctuations, contradicting conventional theories.
Conclusions:
- The findings provide evidence for simultaneous quantum-dynamical scaling and critical Kondo breakdown in YbRh2Si2.
- Macroscopic, scale-invariant fluctuations emerge from microscopic many-body excitations linked to a collapsing Fermi surface.
- This research offers insights into the unconventional behavior of strongly correlated quantum systems at finite temperatures.
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