Atomic-scale images of charge ordering in a mixed-valence manganite

Abstract

Transition-metal perovskite oxides exhibit a wide range of extraordinary but imperfectly understood phenomena. The best known examples are high-temperature superconductivity in copper oxides1, and colossal magnetoresistance in manganese oxides (‘manganites’)2,3. All of these materials undergo a range of order–disorder transitions associated with changes in charge, spin, orbital and lattice degrees of freedom. Measurements of such order are usually made by diffraction techniques, which detect the ionic cores and the spins of the conduction electrons. Unfortunately, because such techniques are only weakly sensitive to valence electrons and yield superpositions of signals from distinct submicrometre-scale phases, they cannot directly image phase coexistence and charge ordering, two key features of the manganites. Here we present scanning tunnelling microscope measurements of the manganite Bi1-xCaxMnO3. We show that charge ordering and phase separation can be resolved in real space with atomic-scale resolution. By taking together images and current–voltage spectroscopy data we find that charge order correlates with both structural order and the local conductive state (either metallic or insulating). These experiments provide an atomic-scale basis for descriptions4 of manganites as mixtures of electronically and structurally distinct phases.

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Figure 1: STM mapping of the paramagnetic phase of Bi0.24Ca0.76MnO3 at 299 K.
Figure 2: Topographic and spectroscopic atomic-scale signatures of phase separation into metallic and insulating regions in the paramagnetic phase of Bi0.24Ca0.76MnO3 at 299 K.
Figure 3: Atomic-scale STM mapping of the charge-ordered phase of Bi0.24Ca0.76MnO3 at 146 K.
Figure 4: Identical lattice periods and electronic structures of the insulating √2a0×√2a0 regions observed in the paramagnetic room-temperature phase (left) and the charge-ordered low-temperature phase (right).

References

  1. 1

    Orenstein, J. & Millis, A. J. Advances in the physics of high-temperature superconductivity. Science 288, 468–474 (2000).

    ADS  CAS  Article  Google Scholar 

  2. 2

    von Helmolt, R., Wecker, J., Holzapfel, B., Schultz, L. & Samwer, K. Giant negative magnetoresistance in perovskite-like La2/3Ba1/3MnOx ferromagnetic films. Phys. Rev. Lett. 71, 2331–2333 (1993).

    ADS  CAS  Article  Google Scholar 

  3. 3

    Jin, S. et al. Thousand–fold change in resistivity in magnetoresistive La-Ca-Mn-O films. Science 264, 413–415 (1994).

    ADS  CAS  Article  Google Scholar 

  4. 4

    Moreo, A., Yunoki, S. & Dagotto, E. Phase separation scenario for manganese oxides and related materials. Science 283, 2034–2040 (1999).

    CAS  Article  Google Scholar 

  5. 5

    Bao, W., Axe, J. D., Chen, C. H. & Cheong, S. -W. Impact of charge ordering on magnetic correlations in perovskite (Bi,Ca)MnO3 . Phys. Rev. Lett. 78, 543–546 (1997).

    ADS  CAS  Article  Google Scholar 

  6. 6

    Wei, J. Y. T., Yeh, N.-C. & Vasquez, R. P. Tunneling evidence of half-metallic ferromagnetism in La0.7Ca0.3MnO3 . Phys. Rev. Lett. 79, 5150–5153 (1997).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Biswas, A., Elizabeth, S., Raychaudhuri, A. K. & Bhat, H. L. Density of states of hole-doped manganites: A scanning-tunneling-microscopy/spectroscopy study. Phys. Rev. B 59, 5368–5376 (1999).

    ADS  CAS  Article  Google Scholar 

  8. 8

    Fäth, M. et al. Spatially inhomogeneous metal-insulator transition in doped manganites. Science 285, 1540–1542 (1999).

    Article  Google Scholar 

  9. 9

    Howald, C., Fournier, P. & Kapitulnik, A. Inherent inhomogeneities in tunneling spectra of Bi2Sr2CaCu2O8-x crystals in the superconducting state. Phys. Rev. B 64, R100504-1–R100504-4 (2001).

    ADS  Article  Google Scholar 

  10. 10

    Pan, S. H. et al. Microscopic electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O8+x . Nature 413, 282–285 (2001).

    ADS  CAS  Article  Google Scholar 

  11. 11

    Radaelli, P. G., Cox, D. E., Marezio, M. & Cheong, S.-W. Charge, orbital, and magnetic ordering in La0.5Ca0.5MnO3 . Phys. Rev. B 55, 3015–3023 (1997).

    ADS  CAS  Article  Google Scholar 

  12. 12

    Su, Y., Du, C.-H., Hatton, P. D., Collins, S. P. & Cheong, S.-W. Charge ordering and the related structural phase transition in single-crystal (Bi0.24Ca0.76)MnO3 . Phys. Rev. B 59, 11687–11692 (1999).

    ADS  CAS  Article  Google Scholar 

  13. 13

    Liu, H. L., Cooper, S. L. & Cheong, S.-W. Optical study of the evolution of charge and spin ordering in the manganese perovskite Bi1-xCaxMnO3 (x>0.5). Phys. Rev. Lett. 81, 4684–4687 (1998).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Billinge, S. J. L., DiFrancesco, R. G., Kwei, G. H., Neumeier, J. J. & Thomson, J. D. Direct observation of lattice polaron formation in the local structure of La1-xCaxMnO3 . Phys. Rev. Lett. 77, 715–718 (1996).

    ADS  CAS  Article  Google Scholar 

  15. 15

    Millis, A. J. Lattice effects in magnetoresistive perovskites. Nature 392, 147–150 (1998).

    ADS  CAS  Article  Google Scholar 

  16. 16

    Woo, H., Tyson, T. A., Croft, M., Cheong, S.-W. & Woicik, J. C. Correlation between the magnetic and structural properties of Ca-doped BiMnO3 . Phys. Rev. B 63, 134412-1–134412-12 (2001).

    ADS  Article  Google Scholar 

  17. 17

    Radaelli, P. G., Cox. D. E., Capogna, L., Cheong, S.-W. & Marezio, M. Wigner-crystal and bi-stripe models for the magnetic and crystallographic superstructures of La0.333Ca0.667MnO3 . Phys. Rev. B 59, 14440–14450 (1999).

    ADS  CAS  Article  Google Scholar 

  18. 18

    Matzdorf, R. et al. Ferromagnetism stabilized by lattice distortion at the surface of the p-wave superconductor Sr2RuO4 . Science 289, 746–748 (2000).

    ADS  CAS  Article  Google Scholar 

  19. 19

    Kagan, M. Yu., Kugel, K. I. & Khomskii, D. I. Phase separation in systems with charge ordering. J. Exp. Theor. Phys. 93, 415–423 (2001).

    ADS  CAS  Article  Google Scholar 

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Acknowledgements

We thank N. Wingreen and J. Chadi for comments on the manuscript, and D. Khomskii, A. Millis, C. de Morais Smith and A. Yazdani for discussions. B.G.K. and S.W.C. were supported by the National Science Foundation.

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Correspondence to Ch. Renner.

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Renner, C., Aeppli, G., Kim, B. et al. Atomic-scale images of charge ordering in a mixed-valence manganite. Nature 416, 518–521 (2002). https://doi.org/10.1038/416518a

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