Structure of superconducting Ca-intercalated bilayer Graphene/SiC studied using total-reflection high-energy positron diffraction

Endo, Yukihiro*; Fukaya, Yuki; Mochizuki, Izumi*; Takayama, Akari*; Hyodo, Toshio*; Hasegawa, Shuji*

Carbon, 157, p.857 - 862, 2020/02

https://doi.org/10.1016/j.carbon.2019.10.070

no abstracts in English

Research progress at the Slow Positron Facility in the Institute of Materials Structure Science, KEK

Hyodo, Toshio*; Wada, Ken*; Mochizuki, Izumi*; Kimura, Masao*; Toge, Nobukazu*; Shidara, Tetsuo*; Fukaya, Yuki; Maekawa, Masaki*; Kawasuso, Atsuo*; Iida, Shimpei*; et al.

Journal of Physics; Conference Series, 791(1), p.012003_1 - 012003_8, 2017/02

https://doi.org/10.1088/1742-6596/791/1/012003

no abstracts in English

Structure determination of the rutile-TiO(110)(12) surface using total-reflection high-energy positron diffraction (TRHEPD)

Mochizuki, Izumi*; Ariga, Hiroko*; Fukaya, Yuki; Wada, Ken*; Maekawa, Masaki*; Kawasuso, Atsuo*; Shidara, Tetsuo*; Asakura, Kiyotaka*; Hyodo, Toshio*

Hyomen Kagaku, 37(9), p.451 - 456, 2016/09

https://doi.org/10.1380/jsssj.37.451

no abstracts in English

Structure determination of the rutile-TiO(110)-(12) surface using total-reflection high-energy positron diffraction (TRHEPD)

Mochizuki, Izumi*; Ariga, Hiroko*; Fukaya, Yuki; Wada, Ken*; Maekawa, Masaki; Kawasuso, Atsuo; Shidara, Tetsuo*; Asakura, Kiyotaka*; Hyodo, Toshio*

Physical Chemistry Chemical Physics, 18(10), p.7085 - 7092, 2016/03

https://doi.org/10.1039/C5CP07892J

no abstracts in English

Brightness enhancement of a linac-based intense positron beam for total-reflection high-energy positron diffraction (TRHEPD)

Maekawa, Masaki; Wada, Ken*; Fukaya, Yuki; Kawasuso, Atsuo; Mochizuki, Izumi*; Shidara, Tetsuo*; Hyodo, Toshio*

European Physical Journal D, 68(6), p.165_1 - 165_6, 2014/06

https://doi.org/10.1140/epjd/e2014-40802-7

Reflection high-energy positron diffraction study on the first surface layer

Fukaya, Yuki; Maekawa, Masaki; Mochizuki, Izumi*; Wada, Ken*; Hyodo, Toshio*; Kawasuso, Atsuo

Journal of Physics; Conference Series, 505, p.012005_1 - 012005_6, 2014/04

https://doi.org/10.1088/1742-6596/505/1/012005

no abstracts in English

Structure of silicene on a Ag(111) surface studied by reflection high-energy positron diffraction

Fukaya, Yuki; Mochizuki, Izumi*; Maekawa, Masaki; Wada, Ken*; Hyodo, Toshio*; Matsuda, Iwao*; Kawasuso, Atsuo

Physical Review B, 88(20), p.205413_1 - 205413_4, 2013/11

https://doi.org/10.1103/PhysRevB.88.205413

no abstracts in English

Atomic configuration and phase transition of Pt-induced nanowires on a Ge(001) surface studied using scanning tunneling microscopy, reflection high-energy positron diffraction, and angle-resolved photoemission spectroscopy

Mochizuki, Izumi; Fukaya, Yuki; Kawasuso, Atsuo; Yaji, Koichiro*; Harasawa, Ayumi*; Matsuda, Iwao*; Wada, Ken*; Hyodo, Toshio*

Physical Review B, 85(24), p.245438_1 - 245438_6, 2012/06

https://doi.org/10.1103/PhysRevB.85.245438

The atomic configuration and electronic band structure of Pt-induced nanowires on a Ge(001) surface are investigated using scanning tunneling microscopy, reflection high-energy positron diffraction, and angle-resolved photoemission spectroscopy. A previously proposed theoretical model, composed of Ge dimers on the top layer and buried Pt arrays in the second and fourth layers, is found to be the fundamental structure of the observed nanowires. At low temperatures ( 80 K), each Ge dimer is alternately tilted in the surface normal direction (asymmetric), causing a p() periodicity. At high temperatures ( 110 K), each Ge dimer is flat with respect to the horizontal axis (symmetric), giving rise to p () periodicity. Upon the above phase transition, the electronic band dispersion related to the Ge dimers in the deeper energy region shifts to the Fermi level.

Reactions of free positrons in low temperature polyethylene; Delayed Ps formation and positron localization

Hirade, Tetsuya; Suzuki, Naoki*; Saito, Fuminori*; Hyodo, Toshio*

Physica Status Solidi (C), 4(10), p.3714 - 3717, 2007/09

https://doi.org/10.1002/pssc.200675742

Positronium (Ps) can be formed by a reaction of trapped electrons and free positrons at low temperatures in molecular solids. While Ps formation by Ore and spur process must be fast, Ps formation by trapped electrons and free positrons is possible even at later positron age. The evidence of this delayed Ps formation was obtained by age-momentum correlation measurement of electron-positron pair annihilation -rays. In this work the parameter curves measured with trapped electrons and no trapped electrons in polyethylene are interpreted by introducing possible positron reactions. Positrons that escape from Ps formation by the Ore and the spur processes have chance to form Ps with trapped electrons. This Ps formation competes with the positron localization resulting from the trapping between molecules or the weakly binding on molecules, ions, or radicals. Assuming the possibility of both the delayed Ps formation and delayed positron trapping and that S-parameters for ortho-Ps and free positrons are the same, we obtain a good fit to the observed time dependent S-parameter curves .

Ag thickness dependence of adatom height for Bi, Pb/Ag(111) surface studied by high brightness reflection high-energy positron diffraction

Fukaya, Yuki; Matsuda, Iwao*; Maekawa, Masaki; Wada, Ken*; Hyodo, Toshio*; Kawasuso, Atsuo

no journal, , 

no abstracts in English