JOPSS - Search Results

We here report a step unbunching phenomenon, which is the inverse of the phenomenon of step bunching. When a 4H-SiC (0001) surface is annealed at a high temperature, step bunching arises due to the different velocities of the step motion in adjacent steps, resulting in steps with a height of more than several nanometers. We found that the bunched steps, thus, obtained by hydrogen etching in an Ar/H $_{2}$ atmosphere were "unbunched" into lower height steps when annealed subsequently at lower temperatures. This unbunching phenomenon can be well explained by the consequence of the competition between energetics and kinetics. Our findings provide another approach for the surface smoothing of SiC by hydrogen etching and may give significant insight into the application of SiC power devices and two-dimensional materials growth techniques in general.

Journal Articles

Neutron spectroscopy evidence on the dual nature of magnetic excitations in a van der Waals metallic ferromagnet Fe $_{2.75}$ GeTe $_{2}$

Bao, S.*; Wang, W.*; Shangguan, Y.*; Cai, Z.*; Dong, Z.-Y.*; Huang, Z.*; Si, W.*; Ma, Z.*; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; et al.

Physical Review X, 12(1), p.011022_1 - 011022_15, 2022/02

https://doi.org/10.1103/PhysRevX.12.011022

Times Cited Count：11 Percentile：78.27(Physics, Multidisciplinary)

Journal Articles

Evidence for strong correlations at finite temperatures in the dimerized magnet Na $_{2}$ Cu $_{2}$ TeO $_{6}$

Shangguan, Y.*; Bao, S.*; Dong, Z.-Y.*; Cai, Z.*; Wang, W.*; Huang, Z.*; Ma, Z.*; Liao, J.*; Zhao, X.*; Kajimoto, Ryoichi; et al.

Physical Review B, 104(22), p.224430_1 - 224430_8, 2021/12

https://doi.org/10.1103/PhysRevB.104.224430

Times Cited Count：1 Percentile：7.92(Materials Science, Multidisciplinary)

Journal Articles

Structure of quasi-free-standing graphene on the SiC (0001) surface prepared by the rapid cooling method

Sumi, Tatsuya*; Nagai, Kazuki*; Bao, J.*; Terasawa, Tomoo; Norimatsu, Wataru*; Kusunoki, Michiko*; Wakabayashi, Yusuke*

Applied Physics Letters, 117(14), p.143102_1 - 143102_5, 2020/10

https://doi.org/10.1063/5.0021071

Times Cited Count：4 Percentile：26.53(Physics, Applied)

A systematic structural study of epitaxial graphene samples on the SiC (0001) surface has been performed by the surface X-ray diffraction method, which is a non-contact technique. For samples with only a buffer layer, one layer graphene, and multilayer graphene, the distances between the buffer layer and the surface Si atoms were found to be 0.23 nm. This value is the same as reported values. For quasi-free-standing graphene samples prepared by the rapid cooling method, there was no buffer layer and the distance between the quasi-free-standing graphene and the surface Si atoms was 0.35 nm, which is significantly shorter than the value in hydrogen-intercalated graphene and slightly longer than the interplane distance in graphite. The Si occupancy deviated from unity within 1 nm of the SiC surface. The depth profile of the Si occupancy showed little sample dependence, and it was reproduced by a simple atomistic model based on random hopping of Si atoms.

Journal Articles

Evidence for magnon-phonon coupling in the topological magnet Cu $_{3}$ TeO $_{6}$

Bao, S.*; Cai, Z.*; Si, W.*; Wang, W.*; Wang, X.*; Shangguan, Y.*; Ma, Z.*; Dong, Z.-Y.*; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; et al.

Physical Review B, 101(21), p.214419_1 - 214419_8, 2020/06

https://doi.org/10.1103/PhysRevB.101.214419

Times Cited Count：17 Percentile：74.78(Materials Science, Multidisciplinary)

Journal Articles

Spin dynamics of a magnetic Weyl semimetal Sr $_{1-x}$ Mn $_{1-y}$ Sb $_{2}$

Cai, Z.*; Bao, S.*; Wang, W.*; Ma, Z.*; Dong, Z.-Y.*; Shangguan, Y.*; Wang, J.*; Ran, K.*; Li, S.*; Kamazawa, Kazuya*; et al.

Physical Review B, 101(13), p.134408_1 - 134408_10, 2020/04

AA2020-0050.pdf:5.09MB

https://doi.org/10.1103/PhysRevB.101.134408

Times Cited Count：6 Percentile：38.95(Materials Science, Multidisciplinary)

Dirac matters provide a platform for exploring the interplay of their carriers with other quantum phenomena. Sr $_{1-x}$ Mn $_{1-y}$ Sb $_{2}$ has been proposed to be a magnetic Weyl semimetal and provides an excellent platform to study the coupling between Weyl fermions and magnons. We performed inelastic neutron scattering measurements on single crystals of Sr $_{1-x}$ Mn $_{1-y}$ Sb $_{2}$ , and found The dispersion in the magnetic Mn layer extends up to about 76 meV, while that between the layers has a narrow band width of 6 meV. Despite the coexistence of Weyl fermions and magnons, we find no clear evidence that the magnetic dynamics are influenced by the Weyl fermions in Sr $_{1-x}$ Mn $_{1-y}$ Sb $_{2}$ , possibly because that the Weyl fermions and magnons reside in the Sb and Mn layers separately, and the interlayer coupling is weak due to the quasi-two-dimensional nature of the material.

Journal Articles

Longitudinal strain of epitaxial graphene monolayers on SiC substrates evaluated by -polarization Raman microscopy

Saito, Yuika*; Tokiwa, Kenshiro*; Kondo, Takahiro*; Bao, J.*; Terasawa, Tomoo; Norimatsu, Wataru*; Kusunoki, Michiko*

AIP Advances (Internet), 9(6), p.065314_1 - 065314_6, 2019/06

https://doi.org/10.1063/1.5099430

Times Cited Count：4 Percentile：16.07(Nanoscience & Nanotechnology)

Journal Articles

Evidence for singular-phonon-induced nematic superconductivity in a topological superconductor candidate Sr $_{0.1}$ Bi $_{2}$ Se $_{3}$

Wang, J.*; Ran, K.*; Li, S.*; Ma, Z.*; Bao, S.*; Cai, Z.*; Zhang, Y.*; Nakajima, Kenji; Kawamura, Seiko; ermk, P.*; et al.

Nature Communications (Internet), 10, p.2802_1 - 2802_6, 2019/06

https://doi.org/10.1038/s41467-019-10942-2

Times Cited Count：21 Percentile：80.49(Multidisciplinary Sciences)

Journal Articles

Selective vibrational excitation in the resonant Auger decay following core-to- transitions in NO

Travnikova, O.*; Colin, D.*; Bao, Z.*; Brve, K. J.*; Tanaka, Takahiro*; Hoshino, Masamitsu*; Kato, Hideki*; Tanaka, Hiroshi*; Harries, J.; Tamenori, Yusuke*; et al.

Journal of Electron Spectroscopy and Related Phenomena, 181(2-3), p.129 - 134, 2010/08

https://doi.org/10.1016/j.elspec.2010.05.006

Times Cited Count：1 Percentile：7.38(Spectroscopy)

In NO a detailed study of the vibrational distribution of the state reached after decay of core-to- excitation of N terminal, N central and O 1s core levels is reported. We observe a change in the relative intensity of bending versus stretching modes while scanning the photon energy across all three resonances. While this effect is known to be due to the Renner-Teller splitting in the core-excited states, we could derive that the antisymmetric stretching is excited mainly in the decay of the N terminal 1s-to- excitation. An explanation for such selectivity is provided in terms of interplay of vibrational structure on potential energy surfaces of different electronic states involved in the process.

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Microscopic origin of the spin-reorientation transition in the kagome topological magnet TbMn $_{6}$ Sn $_{6}$

Direct observation of topological magnon polarons in a multiferroic material

Step unbunching phenomenon on 4H-SiC (0001) surface during hydrogen etching

Neutron spectroscopy evidence on the dual nature of magnetic excitations in a van der Waals metallic ferromagnet Fe $_{2.75}$ GeTe $_{2}$

Evidence for strong correlations at finite temperatures in the dimerized magnet Na $_{2}$ Cu $_{2}$ TeO $_{6}$

Structure of quasi-free-standing graphene on the SiC (0001) surface prepared by the rapid cooling method

Evidence for magnon-phonon coupling in the topological magnet Cu $_{3}$ TeO $_{6}$

Spin dynamics of a magnetic Weyl semimetal Sr $_{1-x}$ Mn $_{1-y}$ Sb $_{2}$

Longitudinal strain of epitaxial graphene monolayers on SiC substrates evaluated by -polarization Raman microscopy

Evidence for singular-phonon-induced nematic superconductivity in a topological superconductor candidate Sr $_{0.1}$ Bi $_{2}$ Se $_{3}$

Selective vibrational excitation in the resonant Auger decay following core-to- transitions in NO