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Singular charge fluctuations at a magnetic quantum critical point
L Prochaska1, X Li2, D C MacFarland1,3
1Institute of Solid State Physics, Technischen Universität (TU) Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria.
Science (New York, N.Y.)
|January 18, 2020
Summary
Researchers studied strange metal behavior in Ytterbium Rhodium Disilicide (YbRh2Si2) using terahertz spectroscopy. They found evidence of critical charge fluctuations, suggesting physics beyond conventional theories for this quantum material.
Area of Science:
- Condensed Matter Physics
- Quantum Materials Science
- Correlated Electron Systems
Background:
- Strange metal behavior is a puzzling phenomenon observed in various correlated materials, including superconductors and graphene.
- Existing theories, often based on Landau's theory of phase transitions, struggle to fully explain these exotic electronic properties.
- Quantum criticality in heavy-fermion systems offers a potential avenue for understanding physics beyond conventional frameworks.
Purpose of the Study:
- To investigate the origins of strange metal behavior in the model compound Ytterbium Rhodium Disilicide (YbRh2Si2).
- To probe the role of critical Kondo entanglement and charge fluctuations in this quantum-critical material.
- To determine if the observed phenomena align with physics beyond the Landau theory of phase transitions.
Main Methods:
- Terahertz time-domain transmission spectroscopy was employed to measure the optical conductivity.
- Thin films of YbRh2Si2 were grown using molecular beam epitaxy.
- Experimental data was analyzed for frequency over temperature scaling.
Main Results:
- Frequency over temperature scaling of optical conductivity was observed in YbRh2Si2.
- This scaling serves as a hallmark of quantum criticality beyond the Landau paradigm.
- The findings provide direct evidence for the significant contribution of charge fluctuations.
Conclusions:
- Critical charge fluctuations are central to the strange metal behavior in YbRh2Si2.
- This research elucidates a long-standing mystery in the field of correlated quantum matter.
- The study supports the existence of exotic quantum physics in heavy-fermion systems.
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