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Probing bulk states of correlated electron systems by high-resolution resonance photoemission

Nature volume 403, pages 396–398 (2000)Cite this article

Abstract

Electron correlations are known to play an important role in determining the unusual physical properties of a variety of compounds. Such properties include high-temperature superconductivity1, heavy fermion behaviour2,3 and metal-to-insulator transitions4,5. High-resolution photoelectron spectroscopy (PES) provides a means of directly probing the electronic states (particularly those near the Fermi level) in these materials, but the short photoelectron mean free paths6 (⩽5 Å) associated with the low excitation energies conventionally used (⩽120 eV) make this a surface-sensitive technique. Now that high-resolution PES is possible at much higher energies7, with mean free paths as long as 15 Å (ref. 6), it should become feasible to probe the bulk electronic states in these materials. Here we demonstrate the power of this technique by applying it to the cerium compounds CeRu2Si2 and CeRu2. Previous PES studies of these compounds revealed very similar spectra for the Ce 4f electronic states8,9,10,11,12,13, yet it is expected that such states should be different owing to their differing degrees of hybridization with other valence bands. Our determination of the bulk Ce 4f electronic states of these compounds resolves these differences.

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Figure 1: Schematic picture of the single impurity Anderson model (SIAM).
Figure 2: Ce 4f spectra obtained from Ce 3d-4f and 4d-4f resonance photoemission, with energy resolution of 200 and 80 meV, respectively.
Figure 3: High-resolution Ce 4f spectra in the 3d-4f (resolution, 100 meV) and 4d-4f (resolution, 50 meV) resonances of CeRu2Si2 and CeRu2.

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References

  1. Bednorz, J. G. & Müller, K. A. Possible high Tc superconductivity in the Ba-La-Cu-O system. Z. Phys. B 64, 189–193 (1986).

    Article  ADS  CAS  Google Scholar 

  2. Sato, N. et al. Magnetic properties of single crystals of CexLa1-xB6. J. Phys. Soc. Jpn 53, 3967–3979 (1986).

    Article  ADS  Google Scholar 

  3. Ônuki, Y. & Komatsubara, T. Heavy fermion state CeCu6. J. Magn. Magn. Mater. 63 & 64, 281–288 (1987).

    Article  Google Scholar 

  4. Nakamura, M. et al. Opening of a correlation-induced band gap in NiS. Phys. Rev. Lett. 73, 2891–2894 (1994).

    Article  ADS  CAS  Google Scholar 

  5. Kuwahara, H. et al. A first-order phase transition induced by a magnetic field. Science 270, 961–963 (1995).

    Article  ADS  CAS  Google Scholar 

  6. Tanuma, S., Powell, C. J. & Penn, D. R. Proposed formula for electron inelastic mean free paths based on calculations for 31 materials. Surf. Sci. 192, L849–L857 (1987).

    Article  ADS  CAS  Google Scholar 

  7. Saitoh, Y. et al. Twin helical undulator beamline for soft x-ray spectroscopy at SPring-8. J. Synchrotron Rad. 5, 542–544 (1998).

    Article  CAS  Google Scholar 

  8. Patthey, F. et al. High-resolution photoemission study of the low-energy excitations in 4f-electron systems. Phys. Rev. B 42, 8864–8881 (1990).

    Article  ADS  CAS  Google Scholar 

  9. Weschke, E. et al. Surface and bulk electronic structure of Ce metal studied by high-resolution resonant photoemission. Phys. Rev. B 44, 8304–8307 (1991).

    Article  ADS  CAS  Google Scholar 

  10. Kaindl, G. et al. Status and perspectives of high-resolution spectroscopy in the soft x-ray range. Rev. Sci. Instrum. 63, 1234–1240 (1992).

    Article  ADS  CAS  Google Scholar 

  11. Joyce, J. J. et al. Temperature-invariant photoelectron spectra in cerium heavy-fermion compounds: Inconsistencies with the Kondo model. Phys. Rev. Lett. 68, 236–239 (1992).

    Article  ADS  CAS  Google Scholar 

  12. Duò, L. et al. The Ce 4f surface shift: A test for the Anderson-impurity Hamiltonian. Phys. Rev. B 54, R17363–R17366 (1996).

    Article  ADS  Google Scholar 

  13. Garnier, M. et al. Applicability of the single impurity model to photoemission spectroscopy of heavy fermion Ce compounds. Phys. Rev. Lett. 78, 4127–4130 (1997).

    Article  ADS  CAS  Google Scholar 

  14. Amato, A. et al. Thermopower and magneto-thermopower of CeRu2Si2 single crystals. J. Magn. Magn. Mater. 76 & 77, 263–264 (1988).

    Article  Google Scholar 

  15. Aoki, H., Uji, S., Albessard, A. K. & Ônuki, Y. Observation of heavy electrons in CeRu2Si2 via the dHvA effect. J. Phys. Soc. Jpn 61, 3457–3461 (1992).

    Article  ADS  CAS  Google Scholar 

  16. Hedo, M. et al. Magnetoresistance and de Haas-van Alphen oscillation in normal and superconducting CeRu2. Phil. Mag. B 77, 975–1000 (1998).

    Article  ADS  CAS  Google Scholar 

  17. Yang, S.-H. et al. High-resolution photoemission study of CeRu2: The dual character of 4f electrons. Phys. Rev. B 53, R11946–R11948 (1996).

    Article  ADS  CAS  Google Scholar 

  18. Kang, J.-S. et al. Photoemission study of an f-electron superconductor: CeRu2. Phys. Rev. B 60, 5348–5353 (1999).

    Article  ADS  CAS  Google Scholar 

  19. Gunnarsson, O. & Schönhammer, K. Photoemission from Ce compounds: Exact model calculation in the limit of large degeneracy. Phys. Rev. Lett. 50, 604–607 (1983).

    Article  ADS  CAS  Google Scholar 

  20. Allen, J. W. et al. Electronic structure of cerium and light rare-earth intermetallics. Adv. Phys. 35, 275–316 (1986).

    Article  ADS  CAS  Google Scholar 

  21. Bickers, N. E., Cox, D. L. & Wilkins, J. W. Thermodynamic, transport and excitation properties of Ce impurities in a model metal: Kondo resonance and universality in the mixed-valent regime. Phys. Rev. Lett. 54, 230–233 (1985).

    Article  ADS  CAS  Google Scholar 

  22. Yeh, J. J. & Lindau, I. Atomic subshell photoionization cross sections and asymmetry parameters 1 ≤ Z ≤ 103. At. Data Nucl. Data Tables 32, 1–155 (1985).

    Article  ADS  CAS  Google Scholar 

  23. Witkowski, N. et al. Resonant photoemission study of the 4f spectral function of cerium in Ce/Fe(100) interfaces. Phys. Rev. B 56, 12054–12057 (1997).

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

We thank S. Ueda, M. Kotsugi, K. Kadono and R.-J. Jung, and the staffs of SPring-8 and PF, especially T. Matsushita, T. Nakatani, T. Muro, K. Mamiya and A. Kakizaki. We also thank S. Imada for discussons. This work was supported by a Grant-in-Aid for COE Research from the Ministry of Education, Science, Sports and Culture of Japan. The work was performed under the approvals of the PF PAC and of the Japan Synchrotron Radiation Research Institute.

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Authors and Affiliations

  1. Department of Material Physics, Graduate School of Engineering Science, Osaka University, Toyonaka, 560-8531, Osaka, Japan

    A. Sekiyama, T. Iwasaki, K. Matsuda & S. Suga

  2. Department of Synchrotron Research, Kansai Research Establishment, Japan Atomic Energy Research Institute, SPring-8, Mikazuki, 679-5148, Hyogo, Japan

    Y. Saitoh

  3. Department of Physics, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Osaka, Japan

    Y. Ônuki

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  1. A. Sekiyama
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Correspondence to A. Sekiyama.

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Sekiyama, A., Iwasaki, T., Matsuda, K. et al. Probing bulk states of correlated electron systems by high-resolution resonance photoemission. Nature 403, 396–398 (2000). https://doi.org/10.1038/35000140

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