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.

Ultrafast energy- and momentum-resolved dynamics of magnetic correlations in the photo-doped Mott insulator Sr2IrO4

Abstract

Measuring how the magnetic correlations evolve in doped Mott insulators has greatly improved our understanding of the pseudogap, non-Fermi liquids and high-temperature superconductivity1,2,3,4. Recently, photo-excitation has been used to induce similarly exotic states transiently5,6,7. However, the lack of available probes of magnetic correlations in the time domain hinders our understanding of these photo-induced states and how they could be controlled. Here, we implement magnetic resonant inelastic X-ray scattering at a free-electron laser to directly determine the magnetic dynamics after photo-doping the Mott insulator Sr2IrO4. We find that the non-equilibrium state, 2 ps after the excitation, exhibits strongly suppressed long-range magnetic order, but hosts photo-carriers that induce strong, non-thermal magnetic correlations. These two-dimensional (2D) in-plane Néel correlations recover within a few picoseconds, whereas the three-dimensional (3D) long-range magnetic order restores on a fluence-dependent timescale of a few hundred picoseconds. The marked difference in these two timescales implies that the dimensionality of magnetic correlations is vital for our understanding of ultrafast magnetic dynamics.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Experimental configuration.
Figure 2: Destruction and recovery of charge and 3D magnetic order in Sr2IrO4.
Figure 3: 2D magnetic correlations before and after photo-excitation.
Figure 4: Fluence dependence of the magnetic and charge dynamics timescales.

References

  1. Scalapino, D. J. A common thread: the pairing interaction for unconventional superconductors. Rev. Mod. Phys. 84, 1383–1417 (2012).

    Article  CAS  Google Scholar 

  2. Kim, Y. et al. Fermi arcs in a doped pseudospin-1/2 Heisenberg antiferromagnet. Science 345, 187–190 (2014).

    Article  CAS  Google Scholar 

  3. Cao, Y. et al. Hallmarks of the Mott-metal crossover in the hole doped pseudospin-1/2 Mott insulator Sr2IrO4 . Nature Commun. 7, 11367 (2016).

    Article  CAS  Google Scholar 

  4. de la Torre, A. et al. Collapse of the Mott gap and emergence of a nodal liquid in lightly doped Sr2IrO4 . Phys. Rev. Lett. 115, 176402 (2015).

    Article  Google Scholar 

  5. Fausti, D. et al. Light-induced superconductivity in a stripe-ordered cuprate. Science 331, 189–191 (2011).

    Article  CAS  Google Scholar 

  6. Zhang, J. & Averitt, R. Dynamics and control in complex transition metal oxides. Annu. Rev. Mater. Res. 44, 19–43 (2014).

    Article  CAS  Google Scholar 

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

    Article  Google Scholar 

  8. Kim, B. J. et al. Phase-sensitive observation of a spin-orbital Mott state in Sr2IrO4 . Science 323, 1329–1332 (2009).

    Article  CAS  Google Scholar 

  9. Kim, J. et al. Magnetic excitation spectra of Sr2IrO4 probed by resonant inelastic X-ray scattering: establishing links to cuprate superconductors. Phys. Rev. Lett. 108, 177003 (2012).

    Article  Google Scholar 

  10. Lee, P. A., Nagaosa, N. & Wen, X.-G. Doping a Mott insulator: physics of high-temperature superconductivity. Rev. Mod. Phys. 78, 17–85 (2006).

    Article  CAS  Google Scholar 

  11. Wang, F. & Senthil, T. Twisted Hubbard model for Sr2IrO4: magnetism and possible high temperature superconductivity. Phys. Rev. Lett. 106, 136402 (2011).

    Article  Google Scholar 

  12. Yan, Y. J. et al. Electron-doped Sr2IrO4: an analogue of hole-doped cuprate superconductors demonstrated by scanning tunneling microscopy. Phys. Rev. X 5, 041018 (2015).

    Google Scholar 

  13. Cao, G., Bolivar, J., McCall, S., Crow, J. E. & Guertin, R. P. Weak ferromagnetism, metal-to-nonmetal transition, and negative differential resistivity in single-crystal Sr2IrO4 . Phys. Rev. B 57, R11039–R11042 (1998).

    Article  CAS  Google Scholar 

  14. Moon, S. J. et al. Electronic structures of layered perovskite Sr2MO4 (M = Ru, Rh, and Ir). Phys. Rev. B 74, 113104 (2006).

    Article  Google Scholar 

  15. Ehrke, H. et al. Photoinduced melting of antiferromagnetic order in La0.5Sr1.5MnO4 measured using ultrafast resonant soft X-ray diffraction. Phys. Rev. Lett. 106, 217401 (2011).

    Article  CAS  Google Scholar 

  16. Zhou, S. et al. Glass-like recovery of antiferromagnetic spin ordering in a photo-excited manganite Pr0.7Ca0.3MnO3 . Sci. Rep. 4, 4050 (2014).

    Article  CAS  Google Scholar 

  17. Chuang, Y. D. et al. Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered La1.75Sr0.25NiO4 nickelate crystals using time-resolved resonant X-ray diffraction. Phys. Rev. Lett. 110, 127404 (2013).

    Article  CAS  Google Scholar 

  18. Caviglia, A. D. et al. Photoinduced melting of magnetic order in the correlated electron insulator NdNiO3 . Phys. Rev. B 88, 220401 (2013).

    Article  Google Scholar 

  19. Lee, W.-S. et al. Phase fluctuations and the absence of topological defects in a photo-excited charge-ordered nickelate. Nature Commun. 3, 838 (2012).

    Article  CAS  Google Scholar 

  20. Boeglin, C. et al. Distinguishing the ultrafast dynamics of spin and orbital moments in solids. Nature 465, 458–461 (2010).

    Article  CAS  Google Scholar 

  21. Kampfrath, T. et al. Coherent terahertz control of antiferromagnetic spin waves. Nature Photon. 5, 31–34 (2011).

    Article  CAS  Google Scholar 

  22. Malinowski, G. et al. Control of speed and efficiency of ultrafast demagnetization by direct transfer of spin angular momentum. Nature Phys. 4, 855–858 (2008).

    Article  CAS  Google Scholar 

  23. Ament, L. J. P., vanVeenendaal, M., Devereaux, T. P., Hill, J. P. & van den Brink, J. Resonant inelastic X-ray scattering studies of elementary excitations. Rev. Mod. Phys. 83, 705–767 (2011).

    Article  CAS  Google Scholar 

  24. Dean, M. P. M. Insights into the high temperature superconducting cuprates from resonant inelastic X-ray scattering. J. Magn. Magn. Mater. 376, 3–13 (2015).

    Article  CAS  Google Scholar 

  25. Batignani, G. et al. Probing ultrafast photo-induced dynamics of the exchange energy in a Heisenberg antiferromagnet. Nature Photon. 9, 506–510 (2015).

    Article  CAS  Google Scholar 

  26. Ishii, K. et al. Momentum-resolved electronic excitations in the Mott insulator Sr2IrO4 studied by resonant inelastic X-ray scattering. Phys. Rev. B 83, 115121 (2011).

    Article  Google Scholar 

  27. Kim, J. et al. Excitonic quasiparticles in a spin–orbit Mott insulator. Nature Commun. 5, 4453 (2014).

    Article  CAS  Google Scholar 

  28. Okamoto, H. et al. Ultrafast charge dynamics in photoexcited Nd2CuO4 and La2CuO4 cuprate compounds investigated by femtosecond absorption spectroscopy. Phys. Rev. B 82, 060513 (2010).

    Article  Google Scholar 

  29. Manousakis, E. The spin-1/2 Heisenberg antiferromagnet on a square lattice and its application to the cuprous oxides. Rev. Mod. Phys. 63, 1–62 (1991).

    Article  CAS  Google Scholar 

  30. Rønnow, H. M. et al. Spin dynamics of the 2d spin quantum antiferromagnet copper deuteroformate tetradeuterate (CFTD). Phys. Rev. Lett. 87, 037202 (2001).

    Article  Google Scholar 

  31. Fujiyama, S. et al. Two-dimensional Heisenberg behavior of Jeff = 1/2 isospins in the paramagnetic state of the spin-orbital Mott insulator Sr2IrO4 . Phys. Rev. Lett. 108, 247212 (2012).

    Article  CAS  Google Scholar 

  32. Vale, J. G. et al. Importance of XY anisotropy in Sr2IrO4 revealed by magnetic critical scattering experiments. Phys. Rev. B 92, 020406 (2015).

    Article  Google Scholar 

  33. Rayan Serrao, C. et al. Epitaxy-distorted spin-orbit Mott insulator in Sr2IrO4 thin films. Phys. Rev. B 87, 085121 (2013).

    Article  Google Scholar 

  34. Chollet, M. et al. The X-ray pump-probe instrument at the LINAC coherent light source. J. Synchrotron Radiat. 22, 503–507 (2015).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

The X-ray scattering work by M.P.M.D., Y.C., V.T. and X.M.C. was supported by the US Department of Energy Basic Energy Sciences Division of Materials Science and Engineering. X.L. acknowledges financial support from MOST (No. 2015CB921302) and CAS (Grant No: XDB07020200) of China. P.J. acknowledges support by Laboratory Directed Research and Development (LDRD) Program 12-007 (Complex Modeling). J.K., D.C. and A.H.S. were supported by the US Department of Energy under Contract No. DE-AC02-06CH11357. S.W. acknowledges financial support from Spanish MINECO (Severo Ochoa grant SEV-2015-0522), Ramon y Cajal programme RYC-2013-14838, Marie Curie Career Integration Grant PCIG12-GA-2013-618487 and Fundació Privada Cellex. J.L. is sponsored by the Science Alliance Joint Directed Research and Development Program at the University of Tennessee. Work in London was supported by the EPSRC. The magnetic Bragg peak measurements were performed at the BL3 of SACLA with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2014B8018). This research made use of the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, which is a DOE Office of Science User Facility, under Contract No. DE-AC02-76SF00515.

Author information

Authors and Affiliations

Authors

Contributions

J.P.H., X.L., M.P.M.D. and M.F. initiated and planned the project. M.P.M.D., Y.C., X.L., S.W., D.Z., R.M., V.T., X.M.C., J.G.V., D.C., J.K., A.H.S., P.J., R.A.-M., J.M.G., A.R., J.R., M.S., S.S., M.K., H.L., L.P., S.O., T.K., M.Y., Y.T., T.T., L.H., C.-L.C., D.F.M., M.F. and J.P.H. prepared for and performed the experiments. M.P.M.D., Y.C., X.L., S.W., M.F., D.F.M. and J.P.H. analysed and interpreted the data. J.L., C.R.S. and B.J.K. prepared the samples. M.P.M.D. and Y.C. wrote the paper with contributions from X.L., S.W., D.F.M., M.F. and J.P.H.

Corresponding authors

Correspondence to M. P. M. Dean, Y. Cao or X. Liu.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 436 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Dean, M., Cao, Y., Liu, X. et al. Ultrafast energy- and momentum-resolved dynamics of magnetic correlations in the photo-doped Mott insulator Sr2IrO4. Nature Mater 15, 601–605 (2016). https://doi.org/10.1038/nmat4641

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nmat4641

This article is cited by

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