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| 2. |
- Song, Jiao-Jiao, et al.
(författare)
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The 4f-Hybridization Strength in CemMnIn3m+2n Heavy-Fermion Compounds Studied by Angle-Resolved Photoemission Spectroscopy
- 2021
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Ingår i: Chinese Physics Letters. - : IOP Publishing. - 0256-307X .- 1741-3540. ; 38:10
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Tidskriftsartikel (refereegranskat)abstract
- We systemically investigate the nature of Ce 4f electrons in structurally layered heavy-fermion compounds CemMnIn3m+2n (with M = Co, Rh, Jr, and Pt, m = 1, 2, n = 0-2), at low temperature using on-resonance angle-resolved photoemission spectroscopy. Three heavy quasiparticle bands f(0), f(7/2)(1) and f(5/2)(1), are observed in all compounds, whereas their intensities and energy locations vary greatly with materials. The strong f(0) states imply that the localized electron behavior dominates the Ce 4f states. The Ce 4f electrons are partially hybridized with the conduction electrons, making them have the dual nature of localization and itinerancy. Our quantitative comparison reveals that the f(5/2)(1)-f (0) intensity ratio is more suitable to reflect the 4f-state hybridization strength.
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| 3. |
- Yuan, Ya Hua, et al.
(författare)
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Angle-resolved photoemission spectroscopy view on the nature of Ce 4f electrons in the antiferromagnetic Kondo lattice CePd5Al2
- 2021
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Ingår i: Physical Review B. - : American Physical Society (APS). - 2469-9969 .- 2469-9950. ; 103:12
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Tidskriftsartikel (refereegranskat)abstract
- We report an angle-resolved photoemission spectroscopy study of the antiferromagnetic Kondo lattice CePd5Al2, focusing on the quasi-two-dimensional k-space nature of its Fermi surface and, tuning photon energy to the Ce 4d-4f on-resonance transition, the hybridization of the Ce 4f state. A strong shoulder feature on the f0 peak was detected, suggesting hybridization between conduction and f bands. On-resonance spectra revealed narrow, yet hybridized quasiparticle bands with sharp peaks and ∼ 9 meV energy dispersion near the Fermi energy EF. The observed dispersive hybridized f band can be well described by a hybridization-band picture based on the periodic Anderson model (PAM). Hence, the 4f electrons in CePd5Al2 display a dual nature, with both localized and itinerant features, but with dominantly localized character.
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| 4. |
- Luo, Yang, et al.
(författare)
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Three-dimensional and temperature-dependent electronic structure of the heavy-fermion compound CePt2In7 studied by angle-resolved photoemission spectroscopy
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:11
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Tidskriftsartikel (refereegranskat)abstract
- The three-dimensional and temperature-dependent electronic structures of the heavy-fermion superconductor CePt2In7 are investigated. Angle-resolved photoemission spectroscopy using variable photon energy establishes the existence of quasi-two- and three-dimensional Fermi surface topologies. Temperature-dependent 4d-4f on-resonance photoemission spectroscopies data reveal that heavy quasiparticle bands begin to form at a temperature well above the characteristic (coherence) temperature T+. The emergence of low-lying crystal electric field excitation may be responsible for the "relocalization" or the precursor to the establishment of heavy electrons coherence in heavy-fermion compounds. These findings provide critical insight into understanding the hybridization in heavy-fermion systems.
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| 5. |
- Yue, Siyao, et al.
(författare)
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Brown carbon from biomass burning imposes strong circum-Arctic warming
- 2022
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Ingår i: ONE EARTH. - : Elsevier BV. - 2590-3330 .- 2590-3322. ; 5:3, s. 293-304
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Tidskriftsartikel (refereegranskat)abstract
- Rapid warming in the Arctic has a huge impact on the global environment. Atmospheric brown carbon (BrC) is one of the least understood and uncertain warming agents due to a scarcity of observations. Here, we performed direct observations of atmospheric BrC and quantified its light-absorbing properties during a 2 month circum-Arctic cruise in summer of 2017. Through observation-constrained modeling, we show that BrC, mainly originated from biomass burning in the mid-to high latitudes of the Northern Hemisphere (similar to 60%), can be a strong warming agent in the Arctic region, especially in the summer, with an average radiative forcing of-90 mW m(-2) (similar to 30% relative to black carbon). As climate change is projected to increase the frequency, intensity, and spread of wildfires, we expect BrC to play an increasing role in Arctic warming in the future.
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