Singular charge fluctuations at a magnetic quantum critical point
Abstract
Strange metal behavior is ubiquitous in correlated materials, ranging from cuprate superconductors to bilayer graphene, and may arise from physics beyond the quantum fluctuations of a Landau order parameter. In quantum-critical heavy-fermion antiferromagnets, such physics may be realized as critical Kondo entanglement of spin and charge and probed with optical conductivity. We present terahertz time-domain transmission spectroscopy on molecular beam epitaxy–grown thin films of YbRh₂Si₂, a model strange-metal compound. We observed frequency over temperature scaling of the optical conductivity as a hallmark of beyond-Landau quantum criticality. Our discovery suggests that critical charge fluctuations play a central role in the strange metal behavior, elucidating one of the long-standing mysteries of correlated quantum matter.
Additional Information
© 2020 American Association for the Advancement of Science. This is an article distributed under the terms of the Science Journals Default License. Received 6 August 2018; resubmitted 7 September 2019. Accepted 5 December 2019. We thank P. Gegenwart, Y.-B. Kim, H. von Löhneysen, S. Nakatsuji, H.-C. Nägerl, and A. Prokofiev for useful discussions. Financial support for this work was provided by the European Research Council (ERC Advanced Grant 227378), the U.S. Army Research Office (ARO W911NF-14-1-0496), the Austrian Science Fund (FWF W1243, P29279-N27, and P29296-N27), and the European Union's Horizon 2020 research and innovation program (grant agreement 824109-EMP). X.L. and J.K. acknowledge financial support from the National Science Foundation (NSF MRSEC DMR-1720595) and the ARO (W911NF-17-1-0259). Q.S. acknowledges financial support from the NSF (DMR-1920740), the Robert A. Welch Foundation (C-1411), and the ARO (W911NF-14-1-0525) and the hospitality of the University of California at Berkeley, the Aspen Center for Physics (NSF grant PHY-1607611), and the Los Alamos National Laboratory (through a Ulam Scholarship from the Center for Nonlinear Studies). This work has also been supported by an InterDisciplinary Excellence Award (IDEA) from Rice University (Q.S., E.R., J.K., and S.P.). Author contributions: S.P. designed and led the research. L.P., D.C.M., A.M.A., W.S., H.D., and G.S. performed the MBE growth. M.B. and A.L. performed the analytical characterization. E.F.B., S.Y., and E.R. performed the TEM investigation. X.L. and J.K. performed the terahertz spectroscopy. Q.S. contributed to the understanding of the results. L.P., X.L., D.C.M., Q.S., and S.P. wrote the manuscript, with contributions from all other authors. The authors have no competing interests. Data and materials availability: All data presented in this paper are deposited in Zenodo (34).Attached Files
Submitted - 1808.02296.pdf
Supplemental Material - aag1595-Prochaska-SM.pdf
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Additional details
- Eprint ID
- 100766
- Resolver ID
- CaltechAUTHORS:20200116-140345082
- 227378
- European Research Council (ERC)
- W911NF-14-1-0496
- Army Research Office (ARO)
- FWF W1243
- FWF Der Wissenschaftsfonds
- P29279-N27
- FWF Der Wissenschaftsfonds
- P29296-N27
- FWF Der Wissenschaftsfonds
- 824109
- European Research Council (ERC)
- DMR-1720595
- NSF
- W911NF-17-1-0259
- Army Research Office (ARO)
- DMR-1920740
- NSF
- C-1411
- Robert A. Welch Foundation
- W911NF-14-1-0525
- Army Research Office (ARO)
- PHY-1607611
- NSF
- Los Alamos National Laboratory
- Rice University
- Created
-
2020-01-16Created from EPrint's datestamp field
- Updated
-
2023-06-01Created from EPrint's last_modified field
- Caltech groups
- Institute for Quantum Information and Matter