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arXiv · 2509.19684

Hybridization gap and $f$-electron effect evolutions with Cd- and Sn-doping in CeCoIn$_5$ via infrared spectroscopy

Myounghoon Lee·Yu-Seong Seo·Seulki Roh·Seokbae Lee·Jihyun Kim·Tuson Park·Jungseek Hwang
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Abstract

We investigated hole (Cd)- and electron (Sn)-doped CeCoIn$_5$ (CeCo(In$_{1-x}T_x$)$_5$ ($T$ = Cd or Sn)) using infrared spectroscopy. Doping-dependent hybridization gap distribution functions were obtained from the optical conductivity spectra based on the periodic Anderson model formalism. The hybridization gap distribution exhibits two components: in-plane and out-of-plane hybridization gaps. The doping-dependent evolution of the two gaps indicated that the out-of-plane gap was more sensitive to doping. Furthermore, the magnetic optical resistivity exhibited a doping-dependent evolution of the $f$-electron amplitude. The two dopant types exhibited different physical properties depending on the level of doping. The Sn dopant increases the $f$-electron amplitude, whereas the Cd dopant does not affect the $f$-electron amplitude. Doping-dependent effective mass is peaked at pure (or undoped) CeCoIn$_5$. Our spectroscopic results may help understand the doping-dependent electronic evolution of one of the canonical heavy fermion systems, CeCoIn$_5$.

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Myounghoon Lee, Yu-Seong Seo, Seulki Roh, Seokbae Lee, Jihyun Kim, Tuson Park, Jungseek Hwang. 2025-09-24. Hybridization gap and $f$-electron effect evolutions with Cd- and Sn-doping in CeCoIn$_5$ via infrared spectroscopy. https://arxiv.org/abs/2509.19684

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