Signature of Kondo hybridisation with an orbital-selective Mott phase in 4d Ca2−xSrxRuO4

Minsoo Kim, Junyoung Kwon, Choong H. Kim, Younsik Kim, Daun Chung, Hanyoung Ryu, Jongkeun Jung, Beom Seo Kim, Dongjoon Song, Jonathan D. Denlinger, Moonsup Han, Yoshiyuki Yoshida, Takashi Mizokawa, Wonshik Kyung*, Changyoung Kim

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The heavy fermion state with Kondo-hybridisation (KH), usually manifested in f-electron systems with lanthanide or actinide elements, was recently discovered in several 3d transition metal compounds without f-electrons. However, KH has not yet been observed in 4d/5d transition metal compounds, since more extended 4d/5d orbitals do not usually form flat bands that supply localised electrons appropriate for Kondo pairing. Here, we report a substitution- and temperature-dependent angle-resolved photoemission study on 4d Ca2−xSrxRuO4, which shows the signature of KH. We observed a spectral weight transfer in the γ-band, reminiscent of an orbital-selective Mott phase (OSMP). The Mott localised γ-band induces the KH with an itinerant β-band, resulting in spectral weight suppression around the Fermi level. Our work demonstrates the evolution of the OSMP with possible KH among 4d electrons, and thereby expands the material boundary of Kondo physics to 4d multi-orbital systems.

Original languageEnglish
Article number59
Journalnpj Quantum Materials
Issue number1
Publication statusPublished - 2022 Dec

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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