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arXiv · 2101.05761

Photoemission signature of momentum-dependent hybridization in CeCoIn$_5$

R. Kurleto·M. Fidrysiak·L. Nicolaï·J. Minár·M. Rosmus·Ł. Walczak·A. Tejeda·J. E. Rault·F. Bertran·A. P. Kądzielawa·D. Legut·D. Gnida·D. Kaczorowski·K. Kissner·F. Reinert·J. Spałek·P. Starowicz
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Abstract

Hybridization between $f$ electrons and conduction bands ($c$-$f$ hybridization) is a driving force for many unusual phenomena. To provide insight into it, systematic studies of CeCoIn$_5$ heavy fermion superconductor have been performed by angle-resolved photoemission spectroscopy (ARPES) in a large angular range at temperature of $T=6$ K. The used photon energy of 122 eV corresponds to Ce $4d$-$4f$ resonance. Calculations carried out with relativistic multiple scattering Korringa-Kohn-Rostoker method and one-step model of photoemission yielded realistic simulation of the ARPES spectra indicating that Ce-In surface termination prevails. Surface states, which have been identified in the calculations, contribute significantly to the spectra. Effects of the hybridization strongly depend on wave vector. They include a dispersion of heavy electrons and bands gaining $f$-electron character when approaching Fermi energy. We have also observed a considerable variation of $f$-electron spectral weight at $E_F$, which is normally determined by both matrix element effects and wave vector dependent $c$-$f$ hybridization. Fermi surface scans covering a few Brillouin zones revealed large matrix element effects. A symmetrization of experimental Fermi surface, which reduces matrix element contribution, yielded a specific variation of $4f$-electron enhanced spectral intensity at $E_F$ around $\bar{\Gamma}$ and $\bar{M}$ points. Tight-binding approximation calculations for Ce-In plane provided the same universal distribution of $4f$-electron density for a range of values of the parameters used in the model.

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R. Kurleto, M. Fidrysiak, L. Nicolaï, J. Minár, M. Rosmus, Ł. Walczak, A. Tejeda, J. E. Rault, F. Bertran, A. P. Kądzielawa, D. Legut, D. Gnida, D. Kaczorowski, K. Kissner, F. Reinert, J. Spałek, P. Starowicz. 2021-01-14. Photoemission signature of momentum-dependent hybridization in CeCoIn$_5$. https://doi.org/10.1103/physrevb.104.125104

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