TY - JOUR
T1 - Temperature-dependent evolution of Ti 3d spectral features at surface of BaxTi8 O16+δ
AU - Dash, S.
AU - Enomoto, H.
AU - Kajita, T.
AU - Ono, K.
AU - Horiba, K.
AU - Kobayashi, M.
AU - Kumigashira, H.
AU - Kandyba, V.
AU - Giampietri, A.
AU - Barinov, A.
AU - Stramaglia, F.
AU - Saini, N. L.
AU - Katsufuji, T.
AU - Mizokawa, T.
N1 - Funding Information:
The synchrotron radiation experiments were performed with the approvals of KEK-Photon Factory, Tsukuba, Japan (Proposal No. 2015G058) and Elettra, Trieste, Italy (Proposal No. 20180309). This work was supported by CREST-JST (Grant No. JPMJCR15Q2) and KAKENHI from JSPS (Grants No. 19H01853 and No. 19H00659). This work was supported by joint research program of ZAIKEN, Waseda University (Project No. 31010).
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/9/24
Y1 - 2019/9/24
N2 - We have studied temperature-driven effects on photoemission spectra of hollandite-type BaxTi8O16+δ across its metal-insulator transition (MIT) at 220 K by using surface-sensitive photon energies from 27 to 70 eV. The surface Ti 3d spectral weight was suppressed and shifted towards higher binding energy from the bulk if the surface was obtained by cleavage above the MIT temperature. The Ti 3d spectral weight was recovered once the sample was cooled across the MIT, indicating a transfer of Ti 3d electrons from the bulk to the surface across the MIT. The recovered Ti 3d spectral shape is consistent with the bulk-sensitive result and indicates strong localization character of the Ti 3d electron even in the metallic phase. Resonant photoemission spectroscopy with absorption from the Ti 3p core level exhibits resonances of the O 2p-Ti 3d and O 2p-Ti 4s,p hybridized states. The result suggests that the O 2p-Ti 4s,p hybridization plays a role in the interplay between the bulk and the surface in BaxTi8O16+δ.
AB - We have studied temperature-driven effects on photoemission spectra of hollandite-type BaxTi8O16+δ across its metal-insulator transition (MIT) at 220 K by using surface-sensitive photon energies from 27 to 70 eV. The surface Ti 3d spectral weight was suppressed and shifted towards higher binding energy from the bulk if the surface was obtained by cleavage above the MIT temperature. The Ti 3d spectral weight was recovered once the sample was cooled across the MIT, indicating a transfer of Ti 3d electrons from the bulk to the surface across the MIT. The recovered Ti 3d spectral shape is consistent with the bulk-sensitive result and indicates strong localization character of the Ti 3d electron even in the metallic phase. Resonant photoemission spectroscopy with absorption from the Ti 3p core level exhibits resonances of the O 2p-Ti 3d and O 2p-Ti 4s,p hybridized states. The result suggests that the O 2p-Ti 4s,p hybridization plays a role in the interplay between the bulk and the surface in BaxTi8O16+δ.
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U2 - 10.1103/PhysRevB.100.125153
DO - 10.1103/PhysRevB.100.125153
M3 - Article
AN - SCOPUS:85072795687
SN - 2469-9950
VL - 100
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
IS - 12
M1 - 125153
ER -