Snapshots of cooperative atomic motions in the optical suppression of charge density waves

Abstract

Macroscopic quantum phenomena such as high-temperature superconductivity, colossal magnetoresistance, ferrimagnetism and ferromagnetism arise from a delicate balance of different interactions among electrons, phonons and spins on the nanoscale1. The study of the interplay among these various degrees of freedom in strongly coupled electron–lattice systems is thus crucial to their understanding and for optimizing their properties. Charge-density-wave (CDW) materials2, with their inherent modulation of the electron density and associated periodic lattice distortion, represent ideal model systems for the study of such highly cooperative phenomena. With femtosecond time-resolved techniques, it is possible to observe these interactions directly by abruptly perturbing the electronic distribution while keeping track of energy relaxation pathways and coupling strengths among the different subsystems3,4,5,6,7. Numerous time-resolved experiments have been performed on CDWs8,9,10,11,12,13, probing the dynamics of the electronic subsystem. However, the dynamics of the periodic lattice distortion have been only indirectly inferred14. Here we provide direct atomic-level information on the structural dynamics by using femtosecond electron diffraction15 to study the quasi two-dimensional CDW system 1T-TaS2. Effectively, we have directly observed the atomic motions that result from the optically induced change in the electronic spatial distribution. The periodic lattice distortion, which has an amplitude of 0.1 Å, is suppressed by about 20% on a timescale (250 femtoseconds) comparable to half the period of the corresponding collective mode. These highly cooperative, electronically driven atomic motions are accompanied by a rapid electron–phonon energy transfer (350 femtoseconds) and are followed by fast recovery of the CDW (4 picoseconds). The degree of cooperativity in the observed structural dynamics is remarkable and illustrates the importance of obtaining atomic-level perspectives of the processes directing the physics of strongly correlated systems.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: FED data in the NCCP in 1T-TaS2.
Figure 2: Time evolution of the diffraction intensities following photoexcitation with a fluence of 2.4 mJ cm−2.
Figure 3: Early time dynamics and emerging time evolution of the CDW state in 1T-TaS 2 on photoexcitation.

References

  1. 1

    Imada, M., Fujimori, A. & Tokura, Y. Metal-insulator transitions. Rev. Mod. Phys. 70, 1039–1263 (1998)

    ADS  CAS  Article  Google Scholar 

  2. 2

    Grüner, G. Density Waves in Solids (Addison-Wesley, 1994)

    Google Scholar 

  3. 3

    Kusar, P. et al. Controlled vaporization of the superconducting condensate in cuprate superconductors by femtosecond photoexcitation. Phys. Rev. Lett. 101, 227001 (2008)

    ADS  CAS  Article  Google Scholar 

  4. 4

    Ogasawara, T. et al. General features of photoinduced spin dynamics in ferromagnetic and ferrimagnetic compounds. Phys. Rev. Lett. 94, 087202 (2005)

    ADS  CAS  Article  Google Scholar 

  5. 5

    Averitt, R. D. et al. Ultrafast conductivity dynamics in colossal magnetoresistance manganites. Phys. Rev. Lett. 87, 017401 (2001)

    ADS  CAS  Article  Google Scholar 

  6. 6

    Rini, M. et al. Control of the electronic phase of a manganite by mode-selective vibrational excitation. Nature 449, 72–74 (2007)

    ADS  CAS  Article  Google Scholar 

  7. 7

    Kübler, C. et al. Coherent structural dynamics and electronic correlations during an ultrafast insulator-to-metal phase transition in VO2 . Phys. Rev. Lett. 99, 116401 (2007)

    ADS  Article  Google Scholar 

  8. 8

    Demsar, J., Biljakovic, K. & Mihailovic, D. Single particle and collective excitations in the one-dimensional charge density wave solid K0. 3MoO3 probed in real time by femtosecond spectroscopy. Phys. Rev. Lett. 83, 800–803 (1999)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Demsar, J. et al. Femtosecond snapshots of gap-forming charge-density-wave correlations in quasi-two-dimensional dichalcogenides 1T-TaS2 and 2H-TaSe2 . Phys. Rev. B 66, 041101 (2002)

    ADS  Article  Google Scholar 

  10. 10

    Yusupov, R. V. et al. Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe3 (R = Ho, Dy, Tb). Phys. Rev. Lett. 101, 246402 (2008)

    ADS  CAS  Article  Google Scholar 

  11. 11

    Perfetti, L. et al. Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition. Phys. Rev. Lett. 97, 067402 (2006)

    ADS  CAS  Article  Google Scholar 

  12. 12

    Schmitt, F. et al. Transient electronic structure and melting of a charge density wave in TbTe3 . Science 321, 1649–1652 (2008)

    ADS  CAS  Article  Google Scholar 

  13. 13

    Tomeljak, A. et al. Dynamics of photoinduced charge-density-wave to metal phase transition in K0. 3MoO3 . Phys. Rev. Lett. 102, 066404 (2009)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Schäfer, H. et al. Disentanglement of the electronic and lattice parts of the order parameter in a 1D charge density wave system probed by femtosecond spectroscopy. Phys. Rev. Lett. 105, 066402 (2010)

    ADS  Article  Google Scholar 

  15. 15

    Miller, R. J. D. et al. ‘Making the molecular movie’: first frames. Acta Crystallogr. A 66, 137–156 (2010)

    ADS  CAS  Article  Google Scholar 

  16. 16

    Williams, P. M., Parry, G. S. & Scruby, C. B. Diffraction evidence for Kohn anomaly in 1T-TaS2 . Phil. Mag. 29, 695–699 (1974)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Wilson, J. A. Di Salvo, F. J. & Mahajan, S. Charge-density waves and superlattices in the metallic layered transition-metal dichalcogenides. Adv. Phys. 24, 117–201 (1975)

    ADS  CAS  Article  Google Scholar 

  18. 18

    Clerc, F. et al. Lattice-distortion-enhanced electron-phonon coupling and Fermi surface nesting in 1T-TaS2 . Phys. Rev. B 74, 155114 (2006)

    ADS  Article  Google Scholar 

  19. 19

    Sipos, B. et al. From Mott state to superconductivity in 1T-TaS2 . Nature Mater. 7, 960–965 (2008)

    ADS  CAS  Article  Google Scholar 

  20. 20

    Fazekas, P. & Tosatti, E. Electrical, structural and magnetic-properties of pure and doped 1T-TaS2 . Phil. Mag. B 39, 229–244 (1979)

    ADS  CAS  Article  Google Scholar 

  21. 21

    Scruby, C. B., Williams, P. M. & Parry, G. S. The role of charge density waves in structural transformations of 1T-TaS2 . Phil. Mag. 31, 255–274 (1975)

    ADS  CAS  Article  Google Scholar 

  22. 22

    Als-Nielsen, J. & McMorrow, D. Elements of Modern X-ray Physics Ch. 4.4.5 (Wiley, 2001)

    Google Scholar 

  23. 23

    Duffey, J. R., Kirby, R. D. & Coleman, R. V. Raman scattering from 1T-TaS2 . Solid State Commun. 20, 617–621 (1976)

    ADS  CAS  Article  Google Scholar 

  24. 24

    Siwick, B. J., Dwyer, J. R., Jordan, R. E. & Miller, R. J. D. An atomic-level view of melting using femtosecond electron diffraction. Science 302, 1382–1385 (2003)

    ADS  CAS  Article  Google Scholar 

  25. 25

    Chergui, M. & Zewail, A. H. Electron and X-ray methods of ultrafast structural dynamics: advances and applications. ChemPhysChem 10, 28–43 (2009)

    CAS  Article  Google Scholar 

  26. 26

    Sciaini, G. et al. Electronic acceleration of atomic motions and disordering in bismuth. Nature 458, 56–59 (2009)

    ADS  CAS  Article  Google Scholar 

  27. 27

    Sokolowski-Tinten, K. et al. Femtosecond X-ray measurement of coherent lattice vibrations near the Lindemann stability limit. Nature 422, 287–289 (2003)

    ADS  CAS  Article  Google Scholar 

  28. 28

    Johnson, S. L. et al. Directly observing squeezed phonon states with femtosecond X-ray diffraction. Phys. Rev. Lett. 102, 175503 (2009)

    ADS  CAS  Article  Google Scholar 

  29. 29

    Fritz, D. M. et al. Ultrafast bond softening in bismuth: mapping a solid’s interatomic potential with X-rays. Science 315, 633–636 (2007)

    ADS  CAS  Article  Google Scholar 

  30. 30

    Beaud, P. et al. Ultrafast structural phase transition driven by photoinduced melting of charge and orbital order. Phys. Rev. Lett. 103, 155702 (2009)

    ADS  CAS  Article  Google Scholar 

Download references

Acknowledgements

We would like to acknowledge discussions with V. V. Kabanov, T. Dekorsy, D. Mihailovic, U. Bovensiepen and M. Wolf, and thank A. Nagy for help in preparing the video in Supplementary Material. This research was supported by the Sofja Kovalevskaja Award of the Alexander von Humboldt Foundation, the Center for Applied Photonics and Zukunftskolleg at the University of Konstanz, the Natural Science and Engineering Research Council of Canada and the Canada Foundation for Innovation. M.E. acknowledges financial support through the Stiftung der Deutschen Wirtschaft. H.B. acknowledges financial support from the Swiss NSF and the NCCR MaNEP.

Author information

Affiliations

Authors

Contributions

R.J.D.M. and J.D. directed this work. H.B. grew 1T-TaS2 single crystals. M.E. and M.K. prepared thin films and performed transmission electron microscopy characterization. G.S., G.M., M.E. and H.S. performed the FED experiments at the University of Toronto. M.B., M.E. and H.S. performed the optical pump–probe experiments at the University of Konstanz. M.E., H.S. and J.D. performed the data analysis. J.D., G.S. and R.J.D.M. wrote the paper. All authors contributed to discussions.

Corresponding authors

Correspondence to Jure Demsar or R. J. Dwayne Miller.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Information comprising Experimental Details and Detailed Data Analysis, Supplementary Figures 1-6 with legends, Legends for Supplementary Movies 1-3 and additional references. (PDF 2126 kb)

Supplementary Movie 1

This movie shows the time evolution of the differential diffraction from -1 to 6 ps with 100 fs time steps, recorded at the excitation density F = 2.4 mJ/cm2. (AVI 2122 kb)

Supplementary Movie 2

This movie shows the animation of the emerging time-evolution of the real-space structure, including both lattice dynamics and the dynamics of the conduction electron density. (AVI 10360 kb)

Supplementary Movie 3

This movie shows the animation of the corresponding changes in the momentum space. (AVI 10175 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Eichberger, M., Schäfer, H., Krumova, M. et al. Snapshots of cooperative atomic motions in the optical suppression of charge density waves. Nature 468, 799–802 (2010). https://doi.org/10.1038/nature09539

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

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