Crossover from a Low-Temperature Heavy-Quasiparticle State to a High-Temperature Local-Moment State in the Heavy-Fermion System

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We investigate the crossover from a low-temperature state in which heavy quasiparticles are formed to the high-temperature state in which conduction electrons separated from the degrees of freedom of f electrons exist in the heavy-fermionic model with the hybridization between conduction electrons and f electrons. To study the temperature dependence of spectral functions, the dynamical mean-field approach is adopted to treat the electron correlation between f electrons. By considering the competition between the effective hybridization energy V* and the characteristic energy I of quasiparticle excitation, it is found that there is a condition, that is, Γ > V*, for a system to show this crossover, whereas for　Γ ≲ V*, the quasiparticle states in the hybridization band become ambiguous with increasing temperature before the effective hybridization between f electrons and conduction electrons is lost.

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References
1 For a review, see, e.g., A. C. Hewson, The Kondo Problem to Heavy Fermions (Cambridge University Press, Cambridge, U.K., 1997).
2 J. H. Shim, K. Haule, and G. Kotliar, Science 318, 1615 (2007). 10.1126/science.1149064
3 A. Georges, G. Kotliar, W. Krauth, and M. J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996). 10.1103/RevModPhys.68.13
4 G. Kotliar, S. Y. Savrasov, K. Haule, V. S. Oudovenko, O. Parcollet, and C. A. Marianetti, Rev. Mod. Phys. 78, 865 (2006). 10.1103/RevModPhys.78.865
5 X. Y. Zhang, M. Rozenberg, and G. Kotliar, Phys. Rev. Lett. 70, 1666 (1993). 10.1103/PhysRevLett.70.1666
6 Although the effect of the f-orbital bandwidth itself on the magnetic correlation in a heavy-fermion model has recently been studied [A. Euverte, S. Chiesa, R. T. Scalettar, and G. G. Batrouni, Phys. Rev. B 88, 235123 (2013)10.1103/PhysRevB.88.235123], the dispersiveness of the f electron is not essential to the present study, as mentioned below.
7 A. Yoshimori and H. Kasai, Solid State Commun. 58, 259 (1986). 10.1016/0038-1098(86)90213-9
(8) Note that the form of the Fermi surface is unchanged by the interaction between electrons under the local approximation of the self-energy.
(9) Strictly speaking, the Fermi surface should be defined at absolute zero, and the expression “the Fermi surface at finite temperature” is used only for convenience and is not correct.
10 J. M. Luttinger, Phys. Rev. 119, 1153 (1960); 10.1103/PhysRev.119.1153 J. M. Luttinger and J. C. Ward, Phys. Rev. 118, 1417 (1960); 10.1103/PhysRev.118.1417 R. M. Martin, Phys. Rev. Lett. 48, 362 (1982). 10.1103/PhysRevLett.48.362
11 G. Aeppli and Z. Fisk, Comments Condens. Matter Phys. 16, 155 (1992).
12 P. Riseborough, Adv. Phys. 49, 257 (2000). 10.1080/000187300243345
(13) We have confirmed a similar temperature dependence of the spectral function of the system with the semicircle density of states for free conduction electrons. The semicircle density of states corresponds to that of the system on the Bethe lattice with a limit of infinite connectivity; it has no singularity in contrast to the system on the square lattice.