Photoelectron spectroscopy of strongly correlated systems: Effects of nonlocal interactions

Jianzhong Zheng; Changfeng Chen

doi:10.1103/PhysRevB.51.14092

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Photoelectron spectroscopy of strongly correlated systems: Effects of nonlocal interactions

Jianzhong Zheng and Changfeng Chen

Department of Physics, University of Nevada, Las Vegas, Nevada 89154

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Phys. Rev. B 51, 14092 – Published 15 May, 1995

DOI: https://doi.org/10.1103/PhysRevB.51.14092

Abstract

We present a theoretical description of the one-particle excitation spectra in strongly correlated systems with nonlocal interactions. Using exact diagonalization techniques, photoemission and inverse photoemission spectra of an extended Hubbard model with an intersite Coulomb interaction are calculated. The single-particle and many-body aspects are treated on an equal footing. The hopping and interaction parameters are adjusted to simulate various Hubbard and charge-transfer systems. In contrast to normal expectations, the intersite interaction is found to suppress the spectral features driven by the on-site interaction, leading to a narrowing in the overall spectral distribution. It also produces qualitatively new behavior in the spin polarization of the spectra and in the doping dependence of the low-energy spectral weight. The degree of sensitivity of the spectra to the single-particle and interaction parameters is systematically investigated. General implications of the calculated results for strongly correlated systems are discussed.

References (18)

For a recent review, see J. W. Allen, The International Conference on Strongly Correlated Electron Systems, Amsterdam, 1994 [Physica B (to be published)].
Z. X. Shen, W. E. Spicer, D. S. Dessau, D. M. King and B. O. Wells, Science 267, 343 (1995), and the references cited therein.
It should be noted that most experimental data show that the density of initial states only describes the photoemission spectra for photon energies in the soft x ray range, or for polycrystalline materials. One should be careful in relating theoretical results to photoemission spectra.
For a recent review, see E. Dagotto, Rev. Mod. Phys. 66, 763 (1994), and references cited therein.
C. Guillot et al., Phys. Rev. Lett. 39, 1632 (1977); D. E. Eastman et al., ibid. 40, 1514 (1978); F. J. Himpsel et al., Phys. Rev. B 19, 2919 (1979); L. A. Feldkamp and L. C. Davis, Phys. Rev. Lett. 43, 151 (1979); W. Eberhardt and E. W. Plummer, Phys. Rev. B 21, 3245 (1980); R. Clauberg et al., Phys. Rev. Lett. 47, 1314 (1981).
D. R. Penn, Phys. Rev. Lett. 42, 921 (1979); A. Liebsch, ibid. 43, 1431 (1979); N. Martensson and B. Johansson, ibid. 45, 482 (1980); L. C. Davis and L. A. Feldkamp, Solid State Commun. 34, 141 (1980); L. Kleinman and K. Mednick, Phys. Rev. B 24, 6880 (1981); R. Clauberg, ibid. 28, 2561 (1983); R. H. Victora and L. M. Falicov, Phys. Rev. Lett. 55, 1140 (1985).
Changfeng Chen, Phys. Rev. Lett. 64, 2176 (1990) , J. Phys. Condens. Matter 4, 9855 (1992) , Phys. Rev. B 45, 13811 (1992) , ibid. 48, 1318 (1993).
S. R. White and R. M. Noack, Phys. Rev. Lett. 68, 3487 (1992); S. R. White, Phys. Rev. B 48, 10345 (1993).
Changfeng Chen, Int. J. Mod. Phys. B 5, 1147 (1991) J. K. Freericks and L. M. Falicov, Phys. Rev. B 42, 4960 (1990).
A. Moreo and E. Dagotto, Phys. Rev. B 42, 4786 (1990); H. J. Schmidt and Y. Kuramoto, ibid. 42, 2562 (1990); E. R. Gagliano, C. A. Balseiro and M. Avignon, Europhys. Lett. 12, 259 (1990).
H. Eskes, M. B. Meinders and G. A. Sawatzky, Phys. Rev. Lett. 67, 1035 (1991).
E. Dagotto, R. Joynt, A. Moreo, S. Bacci and E. Gagliano, Phys. Rev. B 41, 9049 (1990).
M. Tinkham, Group Theory and Quantum Mechanics (McGraw Hill, New York, 1964); A. W. Luehrmann, Adv. Phys. 17, 1 (1968).
L. Tan, Q. Li and J. Callaway, Phys. Rev. B 44, 341 (1991); J. Callaway, J. W. Kim, L. Tan and H. Q. Lin, ibid. 48, 11545 (1993) J. Callaway, L. Tan and H. Zheng, ibid. 50, 1369 (1994).
L. F. Feiner, Phys. Rev. B 48, 16857 (1993).
To illustrate the qualitative physics we can use a dimer model with one electron in the atomic limit. It is easy to find that the energy separation similarly defined as in the PES case is Δ = U - K, which decreases with increasing K.
This shows that the spectral features driven by nonlocal interactions are quite robust. However, photoelectron spectra are usually sensitive to, and sometimes even dominated by, the single particle electronic structure if photon energies are below 60 eV [see, e.g., R. Clauberg, E. M. Haines and R. Feder, Z. Phys. B 62, 31 (1985)].
T. Mizokawa, H. Namatame, A. Fujimori, K. Akeyama, H. Kondoh, H. Kuroda and N. Kosugi, Phys. Rev. Lett. 67, 1638 (1991).

[c1] For a recent review, see J. W. Allen, The International Conference on Strongly Correlated Electron Systems, Amsterdam, 1994 [Physica B (to be published)].

[c2] Z. X. Shen, W. E. Spicer, D. S. Dessau, D. M. King and B. O. Wells, Science 267, 343 (1995), and the references cited therein.

[c3] It should be noted that most experimental data show that the density of initial states only describes the photoemission spectra for photon energies in the soft x ray range, or for polycrystalline materials. One should be careful in relating theoretical results to photoemission spectra.

[c4] For a recent review, see E. Dagotto, Rev. Mod. Phys. 66, 763 (1994), and references cited therein.

[c5] C. Guillot et al., Phys. Rev. Lett. 39, 1632 (1977); D. E. Eastman et al., ibid. 40, 1514 (1978); F. J. Himpsel et al., Phys. Rev. B 19, 2919 (1979); L. A. Feldkamp and L. C. Davis, Phys. Rev. Lett. 43, 151 (1979); W. Eberhardt and E. W. Plummer, Phys. Rev. B 21, 3245 (1980); R. Clauberg et al., Phys. Rev. Lett. 47, 1314 (1981).

[c6] D. R. Penn, Phys. Rev. Lett. 42, 921 (1979); A. Liebsch, ibid. 43, 1431 (1979); N. Martensson and B. Johansson, ibid. 45, 482 (1980); L. C. Davis and L. A. Feldkamp, Solid State Commun. 34, 141 (1980); L. Kleinman and K. Mednick, Phys. Rev. B 24, 6880 (1981); R. Clauberg, ibid. 28, 2561 (1983); R. H. Victora and L. M. Falicov, Phys. Rev. Lett. 55, 1140 (1985).

[c7] Changfeng Chen, Phys. Rev. Lett. 64, 2176 (1990) , J. Phys. Condens. Matter 4, 9855 (1992) , Phys. Rev. B 45, 13811 (1992) , ibid. 48, 1318 (1993).

[c8] S. R. White and R. M. Noack, Phys. Rev. Lett. 68, 3487 (1992); S. R. White, Phys. Rev. B 48, 10345 (1993).

[c9] Changfeng Chen, Int. J. Mod. Phys. B 5, 1147 (1991) J. K. Freericks and L. M. Falicov, Phys. Rev. B 42, 4960 (1990).

[c10] A. Moreo and E. Dagotto, Phys. Rev. B 42, 4786 (1990); H. J. Schmidt and Y. Kuramoto, ibid. 42, 2562 (1990); E. R. Gagliano, C. A. Balseiro and M. Avignon, Europhys. Lett. 12, 259 (1990).

[c11] H. Eskes, M. B. Meinders and G. A. Sawatzky, Phys. Rev. Lett. 67, 1035 (1991).

[c12] E. Dagotto, R. Joynt, A. Moreo, S. Bacci and E. Gagliano, Phys. Rev. B 41, 9049 (1990).

[c13] M. Tinkham, Group Theory and Quantum Mechanics (McGraw Hill, New York, 1964); A. W. Luehrmann, Adv. Phys. 17, 1 (1968).

[c14] L. Tan, Q. Li and J. Callaway, Phys. Rev. B 44, 341 (1991); J. Callaway, J. W. Kim, L. Tan and H. Q. Lin, ibid. 48, 11545 (1993) J. Callaway, L. Tan and H. Zheng, ibid. 50, 1369 (1994).

[c15] L. F. Feiner, Phys. Rev. B 48, 16857 (1993).

[c16] To illustrate the qualitative physics we can use a dimer model with one electron in the atomic limit. It is easy to find that the energy separation similarly defined as in the PES case is Δ = U - K, which decreases with increasing K.

[c17] This shows that the spectral features driven by nonlocal interactions are quite robust. However, photoelectron spectra are usually sensitive to, and sometimes even dominated by, the single particle electronic structure if photon energies are below 60 eV [see, e.g., R. Clauberg, E. M. Haines and R. Feder, Z. Phys. B 62, 31 (1985)].

[c18] T. Mizokawa, H. Namatame, A. Fujimori, K. Akeyama, H. Kondoh, H. Kuroda and N. Kosugi, Phys. Rev. Lett. 67, 1638 (1991).

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