| 1. |
- Cho, Soohyun, et al.
(författare)
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Observation of Dresselhaus type spin splitting of zinc blende structure semiconductors by circular dichroic photoemission study
- 2021
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Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 30, s. 96-101
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Tidskriftsartikel (refereegranskat)abstract
- Material family of zinc blende structure semiconductors (ZBSSs) is important for novel technique such as spintronics. A study of the ZBSS spin-splitting structure in momentum space is essential when seeking to understand the exotic properties of the material. The Dresselhaus field predominates in the bulk, but the Rashba field plays important roles in states near the surface. Here, we used circular dichroism in angle-resolved photoemission spectroscopy (CD-ARPES) to explore the spin-splitting structure of bulk ZBSS in momentum space. The observed structure was well-explained by a Dresselhaus field attributable to the lack of inversion symmetry in ZBSS crystals. We show that CD-ARPES usefully reveals spin-splitting in momentum space. CD-ARPES combined with hard x-ray incident-beam would be useful to investigate the spin-splitting structures of the interface states in the ZBSS heterostructure.
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| 2. |
- Yamaoka, Hithoshi, et al.
(författare)
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Electronic structure and the valence state of Yb2Pd2Sn and YbPd2Sn studied by photoelectron and resonant x-ray emission spectroscopies
- 2012
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 86:8, s. 085137-
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Tidskriftsartikel (refereegranskat)abstract
- We have examined the electronic structure of the heavy fermion Yb2Pd2Sn in comparison with the superconductor YbPd2Sn by means of high-resolution photoelectron spectroscopy (PES) and resonant x-ray emission spectroscopy (RXES). The PES data are interpreted in light of the density of states calculated within the local density approximation plus the dynamical mean-field theory. Our analysis of the RXES data shows that the valence of Yb in Yb2Pd2Sn is weakly fluctuating, indicating weak but finite c-f hybridization, and decreases slightly with temperature. In contrast, the Yb valence in YbPd2Sn is nearly 3+ and does not show any temperature dependence, suggesting that the Yb 4f electrons are localized and the superconductivity is due to the Pd conduction electrons. The constant initial state spectra at the Yb 4d-4f resonance for Yb2Pd2Sn clearly show resonant behavior for Yb3+ and antiresonance for Yb2+, indicating that the Yb3+ and Yb2+ states are intimately correlated.
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| 3. |
- Yamaoka, Hitoshi, et al.
(författare)
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Electronic structure of ferromagnetic heavy fermion, YbPdSi, YbPdGe, and YbPtGe studied by photoelectron spectroscopy, x-ray emission spectroscopy, and DFT plus DMFT calculations
- 2017
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Ingår i: Journal of Physics. - : IOP PUBLISHING LTD. - 0953-8984 .- 1361-648X. ; 29:47
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Tidskriftsartikel (refereegranskat)abstract
- Electronic structures of ferromagnetic heavy fermion Yb compounds of YbPdSi, YbPdGe, and YbPtGe are studied by photoelectron spectroscopy around the Yb 4d-4f resonance, resonant x-ray emission spectroscopy at the Yb L-3 absorption edge, and density functional theory combined with dynamical mean field theory calculations. These compounds all have a temperature-independent intermediate Yb valence with large Yb3+ and small Yb2+ components. The magnitude of the Yb valence is evaluated to be YbPtGe < YbPdGe less than or similar to YbPdSi, suggesting that YbPtGe is the closest to the quantum critical point among the three Yb compounds. Our results support the scenario of the coexistence of heavy fermion behavior and ferromagnetic ordering which is described by a magnetically-ordered Kondo lattice where the magnitude of the Kondo effect and the RKKY interaction are comparable.
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| 4. |
- Yamaoka, Hitoshi, et al.
(författare)
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High-resolution photoelectron spectroscopy study of Kondo metals : SmSn3 and Sm0.9La0.1Sn3
- 2012
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 85:11, s. 115120-
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Tidskriftsartikel (refereegranskat)abstract
- We performed a high-resolution photoelectron spectroscopy study on the Kondo metals SmSn3 and Sm0.9La0.1Sn3. The experimental results are compared with calculations of density of state performed within the local density approximation plus the dynamical mean-field theory. The theory is found to reproduce the experimental valence-band spectra well. In both SmSn3 and Sm0.9La0.1Sn3 the bulk Sm valence is nearly trivalent, with a small fraction of divalent component. Resonant photoelectron spectroscopy indicates a decrease in the Kondo effect in the diluted system Sm0.9La0.1Sn3.
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| 5. |
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