Photoelectron Holographic Atomic Arrangement Imaging of Cleaved Bimetal-intercalated Graphite Superconductor Surface.
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)C8from the cleaved surface was less than a few hundredths of the K 2p peak intensity. These observations indicated that cleavage preferentially occurs at the KC8layers containing no Ca atoms.
Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
Fumihiko
F
Matsui
Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.
Ritsuko
R
Eguchi
Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.
Saki
S
Nishiyama
Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.
Masanari
M
Izumi
Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.
Eri
E
Uesugi
Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.
Hidenori
H
Goto
Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198, Japan.
Tomohiro
T
Matsushita
Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
Kenji
K
Sugita
Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
Hiroshi
H
Daimon
Graduate School of Engineering, Osaka University, Suita 565-0871, Japan.
Yuji
Y
Hamamoto
International Center for Materials Nanoarchitectonics (WPI-MANA) and Global Research Center for Environmental and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki Tsukuba 305-0044, Japan.
Ikutaro
I
Hamada
Graduate School of Engineering, Osaka University, Suita 565-0871, Japan.
Yoshitada
Y
Morikawa
Research Laboratory for Surface Science, Okayama University, Okayama 700-8530, Japan.|Research Centre of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530, Japan.
Yoshihiro
Y
Kubozono