Direct observation of kink evolution due to Hund's coupling on approach to metal-insulator transition in NiS 2-x Se x .

Autor: Jang BG; Department of Chemistry, Pohang University of Science and Technology, Pohang, Korea.; Center for High Pressure Science and Technology Advanced Research, Shanghai, China., Han G; Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, Korea.; Department of Physics and Astronomy, Seoul National University, Seoul, Korea., Park I; Department of Chemistry, Pohang University of Science and Technology, Pohang, Korea., Kim D; Department of Chemistry, Pohang University of Science and Technology, Pohang, Korea., Koh YY; Max Plank POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology, Pohang, Korea., Kim Y; Department of Physics, KAIST, Daejeon, Korea., Kyung W; Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, Korea.; Department of Physics and Astronomy, Seoul National University, Seoul, Korea., Kim HD; Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, Korea.; Department of Physics and Astronomy, Seoul National University, Seoul, Korea.; PAL-XFEL, Pohang Accelerator Laboratory, Pohang, Korea., Cheng CM; National Synchrotron Radiation Research Center, Hsinchu, Taiwan., Tsuei KD; National Synchrotron Radiation Research Center, Hsinchu, Taiwan., Lee KD; Department of Physics, Inha University, Incheon, Republic of Korea., Hur N; Department of Physics, Inha University, Incheon, Republic of Korea., Shim JH; Department of Chemistry, Pohang University of Science and Technology, Pohang, Korea. jhshim@postech.ac.kr.; Department of Physics, Pohang University of Science and Technology, Pohang, Korea. jhshim@postech.ac.kr.; Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, Korea. jhshim@postech.ac.kr., Kim C; Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, Korea. changyoung@snu.ac.kr.; Department of Physics and Astronomy, Seoul National University, Seoul, Korea. changyoung@snu.ac.kr., Kotliar G; Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2021 Feb 23; Vol. 12 (1), pp. 1208. Date of Electronic Publication: 2021 Feb 23.
DOI: 10.1038/s41467-021-21460-5
Abstrakt: Understanding characteristic energy scales is a fundamentally important issue in the study of strongly correlated systems. In multiband systems, an energy scale is affected not only by the effective Coulomb interaction but also by the Hund's coupling. Direct observation of such energy scale has been elusive so far in spite of extensive studies. Here, we report the observation of a kink structure in the low energy dispersion of NiS 2-x Se x and its characteristic evolution with x, by using angle resolved photoemission spectroscopy. Dynamical mean field theory calculation combined with density functional theory confirms that this kink originates from Hund's coupling. We find that the abrupt deviation from the Fermi liquid behavior in the electron self-energy results in the kink feature at low energy scale and that the kink is directly related to the coherence-incoherence crossover temperature scale. Our results mark the direct observation of the evolution of the characteristic temperature scale via kink features in the spectral function, which is the hallmark of Hund's physics in the multiorbital system.
Databáze: MEDLINE
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