TY - JOUR
T1 - Photoelectron Holographic Atomic Arrangement Imaging of Cleaved Bimetal-intercalated Graphite Superconductor Surface
AU - Matsui, Fumihiko
AU - Eguchi, Ritsuko
AU - Nishiyama, Saki
AU - Izumi, Masanari
AU - Uesugi, Eri
AU - Goto, Hidenori
AU - Matsushita, Tomohiro
AU - Sugita, Kenji
AU - Daimon, Hiroshi
AU - Hamamoto, Yuji
AU - Hamada, Ikutaro
AU - Morikawa, Yoshitada
AU - Kubozono, Yoshihiro
N1 - Funding Information:
This study was partly supported by Grants-in-Aid (22244045, 24654105, 25287075, 26105004, 26105007, and 26105010) from MEXT and by the Program for Promoting the Enhancement of Research Universities. The photoelectron holography measurements at SPring-8 were supported by 2015A0124 and 2015B1007. K.P. thanks the EPSRC for providing support (EP/K027255). Y.K. is grateful for the support from the LEMSUPER project (JST-EU Superconductor Project) of the Japan Science and Technology Agency (JST) and the ACT-C project of Japan. I. H. acknowledges the financial support from MEXT through the "World Premier International Research Center Initiative (WPI)," and the "Development of Environmental Technology using Nanotechnology" program.
Publisher Copyright:
© The Author(s) 2016.
PY - 2016/11/4
Y1 - 2016/11/4
N2 - From the C 1s and K 2p photoelectron holograms, we directly reconstructed atomic images of the cleaved surface of a bimetal-intercalated graphite superconductor, (Ca, K)C8, which differed substantially from the expected bulk crystal structure based on x-ray diffraction (XRD) measurements. Graphene atomic images were collected in the in-plane cross sections of the layers 3.3 Å and 5.7 Å above the photoelectron emitter C atom and the stacking structures were determined as AB- and AA-type, respectively. The intercalant metal atom layer was found between two AA-stacked graphenes. The K atomic image revealing 2 × 2 periodicity, occupying every second centre site of C hexagonal columns, was reconstructed, and the Ca 2p peak intensity in the photoelectron spectra of (Ca, K)C8 from the cleaved surface was less than a few hundredths of the K 2p peak intensity. These observations indicated that cleavage preferentially occurs at the KC8 layers containing no Ca atoms.
AB - From the C 1s and K 2p photoelectron holograms, we directly reconstructed atomic images of the cleaved surface of a bimetal-intercalated graphite superconductor, (Ca, K)C8, which differed substantially from the expected bulk crystal structure based on x-ray diffraction (XRD) measurements. Graphene atomic images were collected in the in-plane cross sections of the layers 3.3 Å and 5.7 Å above the photoelectron emitter C atom and the stacking structures were determined as AB- and AA-type, respectively. The intercalant metal atom layer was found between two AA-stacked graphenes. The K atomic image revealing 2 × 2 periodicity, occupying every second centre site of C hexagonal columns, was reconstructed, and the Ca 2p peak intensity in the photoelectron spectra of (Ca, K)C8 from the cleaved surface was less than a few hundredths of the K 2p peak intensity. These observations indicated that cleavage preferentially occurs at the KC8 layers containing no Ca atoms.
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U2 - 10.1038/srep36258
DO - 10.1038/srep36258
M3 - Article
AN - SCOPUS:84994589640
VL - 6
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
M1 - 36258
ER -