Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Time-resolved collapse and revival of the Kondo state near a quantum phase transition

Abstract

One of the most successful paradigms of many-body physics is the concept of quasiparticles: excitations in strongly interacting matter behaving like weakly interacting particles in free space. Quasiparticles in metals are very robust objects. Nevertheless, when a system’s ground state undergoes a qualitative change at a quantum critical point (QCP)1, the quasiparticles may disintegrate and give way to an exotic quantum-fluid state of matter. The nature of this breakdown is intensely debated2,3,4,5, because the emergent quantum fluid dominates material properties up to high temperatures and might even be related to the occurrence of superconductivity in some compounds6. Here we trace the dynamics of heavy-fermion quasiparticles in CeCu6−xAux and monitor their evolution towards the QCP in time-resolved experiments, supported by many-body calculations. A terahertz pulse disrupts the many-body heavy-fermion state. Under emission of a delayed, phase-coherent terahertz reflex the heavy-fermion state recovers, with a coherence time 100 times longer than typically associated with correlated metals7,8. The quasiparticle weight collapses towards the QCP, yet its formation temperature remains constant—phenomena believed to be mutually exclusive. Coexistence in the same experiment calls for revisions in our view on quantum criticality.

This is a preview of subscription content, access via your institution

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Fig. 1: Heavy-fermion quasiparticles near a QCP.
Fig. 2: Time-resolved terahertz reflectivity of the heavy-fermion system CeCu6−xAux.
Fig. 3: Dynamics of heavy-fermion quasiparticle formation.
Fig. 4: Evolution of Kondo weight and Kondo temperature towards the QCP in the CeCu6−xAux system.

References

  1. v. Löhneysen, H., Rosch, A., Vojta, M. & Wölfle, P. Fermi-liquid instabilities at magnetic quantum phase transitions. Rev. Mod. Phys. 79, 1015–1075 (2007).

    ADS  Article  Google Scholar 

  2. Si, Q., Rabello, S., Ingersent, K. & Smith, J. L. Locally critical quantum phase transitions in strongly correlated metals. Nature 413, 804–808 (2001).

    ADS  Article  Google Scholar 

  3. Coleman, P., Pépin, C., Si, Q. & Ramazashvili, R. How do Fermi liquids get heavy and die?. J. Phys.Condens. Mat. 13, R723–R738 (2001).

    ADS  Article  Google Scholar 

  4. Senthil, T., Vojta, M. & Sachdev, S. Weak magnetism and non-Fermi liquids near heavy-fermion critical points. Phys. Rev. B 69, 035111 (2004).

    ADS  Article  Google Scholar 

  5. Wölfle, P. & Abrahams, E. Quasiparticles beyond the Fermi liquid and heavy fermion criticality. Phys. Rev. B 84, 041101(R) (2011).

    ADS  Article  Google Scholar 

  6. Kenzelmann, M. et al. Coupled superconducting and magnetic order in CeCoIn5. Science 321, 1652–1654 (2008).

    ADS  Article  Google Scholar 

  7. Knoesel, E., Hotzel, A. & Wolf, M. Ultrafast dynamics of hot electrons and holes in copper: Excitation, energy relaxation, and transport effects. Phys. Rev. Lett. 57, 12812–12824 (1998).

    Google Scholar 

  8. Kummer, K. et al. Ultrafast quasiparticle dynamics in the heavy-fermion compound YbRh2Si2. Phys. Rev. B 86, 085139 (2012).

    ADS  Article  Google Scholar 

  9. Wölfle, P. Quasiparticles in condensed matter systems. Rep. Prog. Phys. 81, 032501 (2018).

    ADS  MathSciNet  Article  Google Scholar 

  10. Ruderman, M. A. & Kittel, C. Indirect exchange coupling of nuclear magnetic moments by conduction electrons. Phys. Rev. 96, 99–102 (1954).

    ADS  Article  Google Scholar 

  11. Kasuya, T. A theory of metallic ferromagnetism and antiferromagnetism on Zener’s model. Prog. Theor. Phys. 16, 45–57 (1956).

    ADS  Article  Google Scholar 

  12. Yosida, K. Magnetic properties of Cu–Mn alloys. Phys. Rev. 106, 893–898 (1957).

    ADS  Article  Google Scholar 

  13. Kondo, J. Resistance minimum in dilute magnetic alloys. Prog. Theor. Phys. 32, 37–49 (1964).

    ADS  Article  Google Scholar 

  14. Hewson, A. C. The Kondo Problem to Heavy Fermions (Cambridge University Press, Cambridge, 1993).

    Book  Google Scholar 

  15. Hertz, J. A. Quantum critical phenomena. Phys. Rev. B 14, 1165–1184 (1976).

    ADS  Article  Google Scholar 

  16. Moriya, T. Spin Fluctuations in Itinerant Electron Magnetism. (Springer: Berlin, 1985).

    Book  Google Scholar 

  17. Millis, A. Effect of a nonzero temperature on quantum critical points in itinerant fermion systems. Phys. Rev. B 48, 7183–7196 (1993).

    ADS  Article  Google Scholar 

  18. Schröder, A. et al. Onset of antiferromagnetism in heavy-fermion metals. Nature 407, 351–355 (2000).

    ADS  Article  Google Scholar 

  19. Stroka, B. et al. Crystal-field excitations in the heavy-fermion alloys CeCu6−xAux studied by specific heat and inelastic neutron scattering. Z. Phys. B 90, 155–160 (1993).

    ADS  Article  Google Scholar 

  20. Ehm, D. et al. High-resolution photoemission study on low-T K Ce systems: Kondo resonance, crystal field structures, and their temperature dependence. Phys. Rev. B 76, 045117 (2007).

    ADS  Article  Google Scholar 

  21. Klein, M. et al. Signature of quantum criticality in photoemission spectroscopy at elevated temperature. Phys. Rev. Lett. 101, 266404 (2008).

    ADS  Article  Google Scholar 

  22. Doniach, S. The Kondo lattice and weak antiferromagnetism. Physica B 91, 231–234 (1977).

    Article  Google Scholar 

  23. Marabelli, F. & Wachter, P. Temperature dependence of the optical conductivity of the heavy-fermion system CeCu6. Phys. Rev. B 42, 3307–3311 (1990).

    ADS  Article  Google Scholar 

  24. v. Löhneysen, H. et al. Rare-earth intermetallic compounds at a magnetic instability. J. Alloy. Comp. 408–412, 9–15 (2006).

    Article  Google Scholar 

  25. v. Löhneysen, H., Sieck, M., Stockert, O. & Waffenschmidt, M. Investigation of non-Fermi-liquid behavior in CeCu6−xAux. Physica B 223 & 224, 471–474 (1996).

    Article  Google Scholar 

  26. Schröder, A., Lynn, J. W., Erwin, R. W., Loewenhaupt, M. & v. Löhneysen, H. Magnetic structure of the heavy fermion alloy CeCu5.5Au0.5. Physica B 199 & 200, 47–48 (1994).

    Article  Google Scholar 

  27. Stockert, O., v. Löhneysen, H., Rosch, A., Pyka, N. & Loewenhaupt, M. Two-dimensional fluctuations at the quantum-critical point of CeCu6−xAux. Phys. Rev. Lett. 80, 5627–5630 (1998).

    ADS  Article  Google Scholar 

  28. v. Löhneysen, H. et al. Heavy-fermion systems at the magnetic-nonmagnetic quantum phase transition. J. Mag. Mag. Mat. 177-181, 12–17 (1998).

    ADS  Article  Google Scholar 

  29. Rosch, A., Schröder, A., Stockert, O. & v. Löhneysen, H. Mechanism for the non-Fermi-liquid behavior in CeCu6−xAux. Phys. Rev. Lett. 79, 159–162 (1997).

    ADS  Article  Google Scholar 

  30. Nejati, A., Ballmann, K. & Kroha, J. Kondo destruction in RKKY-coupled Kondo lattice and multi-impurity systems. Phys. Rev. Lett. 118, 117204 (2017).

    ADS  Article  Google Scholar 

  31. Aoki, H. et al. Nonequilibrium dynamical mean-field theory and its applications. Rev. Mod. Phys. 86, 779–837 (2014).

    ADS  Article  Google Scholar 

  32. Kroha, J. & Wölfle, P. Fermi and non-Fermi liquid behavior in quantum impurity systems: Conserving slave boson theory. Acta Phys. Pol. B 29, 3781–3817 (1998).

    ADS  Google Scholar 

  33. Hettler, M. H., Kroha, J. & Hershfield, S. Non-equilibrium dynamics of the Anderson impurity model. Phys. Rev. Lett. 58, 5649–5664 (1998).

    ADS  Google Scholar 

Download references

Acknowledgements

The authors are grateful for financial support by the SNSF via project No. 200021-14708 (M.F., C.W.) and by the DFG via SFB/TR 185 (J.K).

Author information

Authors and Affiliations

Authors

Contributions

All authors contributed to the discussion and interpretation of the experiment and to the completion of the manuscript. C.W. and S.P. performed the experiment and the data analysis. O.S. and H.v.L. provided the CeCu6−xAux samples. K.K. and C.K. provided YbRh2Si2 samples for reference experiments. J.K. performed the theoretical analysis. J.K. and M.F. initiated the experiment and supervised the work.

Corresponding authors

Correspondence to J. Kroha or M. Fiebig.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

3 Figures, 3 References

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wetli, C., Pal, S., Kroha, J. et al. Time-resolved collapse and revival of the Kondo state near a quantum phase transition. Nature Phys 14, 1103–1107 (2018). https://doi.org/10.1038/s41567-018-0228-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41567-018-0228-3

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing