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解説、著書 |
メディア紹介 |
学会発表 |
Direct observation of pressure-induced amorphization of methane/ethane
hydrates using Raman and infrared spectroscopy
N. Noguchi, Y. Shiraishi, Maho Kageyama, Y. Yokoi, S. Kurohama, N. Okada,
H. Okamura,
Phys. Chem. Chem. Phys. 25 (2023) 22161.
Pressure suppression of the excitonic insulator state in Ta2NiSe5 studied by optical conductivity
H. Okamura, T. Mizokawa, K. Miki, Y. Matsui, N. Noguchi, N. Katayama, H.
Sawa, M. Nohara, Y. Lu, H. Takagi, T. Moriwaki, Y. Ikemoto,
Phys. Rev. B 107 (2023) 045141.
Pressure Induced Spectral Redistribution Due to Te2 Dimer Breaking in AuTe2
D. Ootsuki, H. Okamura, S. Mitsumoto, Y. Ikemoto, T. Moriwaki, M. Arita,
T. Yoshida, K. Kudo, H. Ishii, M. Nohara, T. Mizokawa.
J. Phys. Soc. Jpn. 90 (2021) 114705.
Hybridization-gap Formation and Superconductivity in the Pressure-induced
Semimetallic Phase of the Excitonic Insulator Ta2NiSe5
K. Matsubayashi, H. Okamura, T. Mizokawa, N. Katayama, A. Nakano, H. Sawa,
T. Kaneko, T. Toriyama, T. Konishi, Y. Ohta, H. Arima, R. Yamanaka, A.
Hisada, T. Okada, Y. Ikemoto, T. Moriwaki, K. Munakata, A. Nakao, M. Nohara,
Y. Lu, H. Takagi, Y. Uwatoko,
J. Phys. Soc. Jpn. 90 (2021) 074706. (Paper of Editors' Choice) (JPS Hot Topics)
Robust hybridization gap in the Kondo insulator YbB12 probed by femtosecond optical spectroscopy
A. R. Pokharel, S. Y. Agustsson, V. V. Kabanov, F. Iga, T. Takabatake,
H. Okamura, J. Demdar,
Phys. Rev. B 103 (2021) 115134.
Infrared and Raman Spectroscopic Study of Methan Clathrate Hydrates at
Low Temperatures and High Pressures: Dynamics and Cage Occupancy of Methane
N. Noguchi, T. Yonezawa, Y. Yokoi, T. Tokunaga, T. Moriwaki, Y. Ikemoto,
H. Okamura
J. Phys. Chem. C 125 (2021) 189-200.
Optical Conductivity Study of f Electron States in YbCu2Ge2 at High Pressures to 20 GPa
H. Okamura, M. Nagata, A. Tsubouchi, Y. Onuki, Y. Ikemoto, T. Moriwaki
JPS Conf. Proc. 30 (2020) 011120.
Contrasting pressure evolutions of f electron hybridized states in CeRhIn5 and YbNi3Ga9: an optical conductivity study
H. Okamura, A. Takigawa, T. Yamasaki, E. D. Bauer, S. Ohara, Y. Ikemoto,
T. Moriwaki
Phys. Rev. B 100, 195112 (2019).
Rheological property of H2O ice VI inferred from its self-diffusion : Implications for the mantle
dynamics of large icy bodies
N. Noguchi and T.Okuchi
Icarus 335, 113401 (2019).
Pluto’s ocean is capped and insulated by gas hydrates
S. Kamata, F. Nimmo, Y. Sekine, K. Kuramoto, N. Noguchi, J. Kimura & A. Tani
Nature Geoscience 12, 407-410 (2019).
Infrared spectroscopy on electronic structures of platinum-group metal
pernitrides MN2 (M = Ru, Rh, Ir, and Pt)
K. Soda, M. Komabuchi, K. Maeguchi, M. Kato, T. Terabe, K. Niwa, M. Hasegawa,
Y. Ikemoto, H. Okamura
Physica B 558, 54 (2019).
Infrared spectroscopy techniques for studying the electronic structures
of materials under high-pressure
H. Okamura, Y. Ikemoto, T. Moriwaki, T. Nanba
Jpn. J. Appl. Phys.56 (2017) 05FA11.
Pressure dependence of far-infrared spectra in layered iron oxide LuFeO4
T. Go, H. Okamura, G. Ohhara, T. Nagata, T. Moriwaki, Y. Ikemoto, S. Mori,
N. Ikeda, K. Mizoguchi
Trans. Mater. Soc. Jpn, 41 (2016) 109-112.
Pressure Evolution of f electron hybridized state in CeCoIn5 studied by optical conductivity
H. Okamura, A. Takigawa, E. D. Bauer, T. Moriwaki, Y. Ikemoto
J. Phys. Conf. Ser. 592 (2015) 012001.
Emergence of charge degrees of freedom under high pressure in the organic
dimer-Mott insulator β'-(BEDT-TTF)2ICl2
K. Hashimoto, R. Kobayashi, H. Okamura, H. Taniguchi, Y. Ikemoto, T. Moriwaki,
S. Iguchi, M. Naka, S. Ishihara, T. Sasaki,
Phys. Rev. B 92 (2015) 085149.
Improvement of infrared near-field spectrum by asymmetric interferometer
onfiguration
Y. Ikemoto, H. Okamura, T. Moriwaki, H. Suto, T. Kinoshita,
Jpn. J. Appl. Phys. 54 (2015) 082402.
Pressure Supression of Spin-Density-Wave gap in the Optical Conductivity
of SrFe2As2
H. Okamura, K. Shoji, M. Miyata, H. Sugawara, T. Moriwaki, Y. Ikemoto
J. Phys. Soc. Jpn. 82 (2013) 074720.
Infrared and Terahertz Spectroscopy of Strongly Correlated Electron Systems
under Extreme Conditions
S. Kimura and H. Okamura
J. Phys. Soc. Jpn. 82 (2013) 021004. (Special Topics "Frontier of Condensed Matter Physics using Synchrotron
Radiation)
Pressure suppression of unconventional charge-density-wave state in PrRu4P12 studied by optical conductivity
H. Okamura, N. Ohta, A. Takigawa, I. Matsutori, K. Shoji, K. Miyata, M.
Matsunami, H. Sugawara, C. Sekine, I. Shirotani, H. Sato, T. Moriwaki,
Y. Ikemoto, Z. Liu, G. L. Carr
Phys. Rev. B 85 (2012) 205115.
Broadband near-field mid-infrared spectroscopy and application to phonon
resonances in quartz
M. Ishikawa, M. Katsura, S. Nakashima, Y. Ikemoto, H. Okamura
Opt. Express 20 (2012) 11064-11072.
A simple method for the Kramers-Kronig analysis of reflectance data measured
with diamond anvil cell
H. Okamura
J. Phys. Conf. Ser. 359 (2012) 012013.
Development of Scattering Near-Field Optical Microspectroscopy Apparatus
Using an Infrared Synchrotron Radiation Source
Y. Ikemoto, M. Ishikawa, S. Nakashima, H. Okamura, Y. Haruyama, S. Matsui,
T. Moriwaki, T. Kinoshita
Opt. Commun. 285 (2012) 2212-2217.
Photoinduced Dynamics in Pure and Ca-Doped SrTiO3 Studied by Transient
Birefringence and Absorption Measurements
T. Kohmoto, Y. Koyama, T. Moriyasu, H. Okamura, Y. Yamada, K. Tanaka
J. Phys. Soc. Jpn. 80 (2011) 104605.
Optical Conductivity and Electronic Structure of CeRu4Sb12 under High Pressure
H. Okamura, R. Kitamura, M. Matsunami, H. Sugawara, H. Harima, H. Sato,
T. Moriwaki, Y. Ikemoto, T. Nanba
J. Phys. Soc. Jpn. 80 (2011) 084718.
Modulated near-field spectral extraction of broadband mid-infrared signals
with a ceramic light source
M. Ishikawa, M. Katsura, S. Nakashima, K. Aizawa, T. Inoue, H. Okamura,
Y. Ikemoto
Opt. Express 19 (2011) 12469.
Suppression of Metal-Insulator Transition in PrRu4P12 under High Pressure Studied by Infrared Spectroscopy
H. Okamura, I. Matsutori, A. Takigawa, K. Shoji, K. Miyata, M. Matsunami,
H. Sugawara, H. Sato, C. Sekine, I. Shirotani, T. Moriwaki, Y. Ikemoto,
T. Nanba
Proceedings of the International Conference on Heavy Electrons (Tokyo,
2010)
J. Phys. Soc. Jpn. 80 (2011) SA092.
Near-Field Spectroscopy with Infrared Synchrotron Radiation Source
Y. Ikemoto, T. Moriwaki, T. Kinoshita, M. Ishikawa, S. Nakashima, and H. Okamura
e-Journal of Surf. Sci. and Nanotech. 9 (2011) 63-66.
Application of a Modulating Techniaue to Detect Near-Field Signals Using
a Conventional IR Spectrometer with a Ceramic Light Source
M. Ishikawa, M. Katsura, S. Nakashima, K. Aizawa, T. Inoue, Y. Ikemoto,
H. Okamura
e-Journal of Surf. Sci. and Nanotech. 9 (2011) 40-45.
High pressure infrared studies of correlated electron materials using synchrotron
radiation
H. Okamura, M. Matsunami, R. Kitamura, A. Ochiai, H. Sugawara, H. Sato,
T. Moriwaki, Y. Ikemoto, T. Nanba
10.1109/ICIMW.2010.5612372
Infrared studies of f electron systems under high pressure using synchrotron radiation
H.Okamura, M.Matsunami, R.Kitamura, S.Ishida, T.Nanba
J. Phys. Conf. Ser. 215 (2010) 012051.
Doping-induced ferroelectric phase transition in strontium titanate: Observation
of birefringence and coherent phonons under ultraviolet illumination
Y. Koyama, T. Moriyasu, H. Okamura, Y. Yamada, K. Tanaka, and T. Kohmoto
Phys. Rev. B 81 (2010) 024104.
High pressure infrared studies of correlated electron materials at SPring-8
H. Okamura, R. Kitamura, M. Matsunami, T. Nanba, H. Sugawara, and H. Sato
AIP Conf. Ser. 1214 (2010), 75.
Pressure Tuning of an Ionic Insulator into a Heavy Electron Metal: An Infrared
Study of YbS
M. Matsunami, H. Okamura, A. Ochiai, and T. Nanba
Phys. Rev. Lett. 103 (2009) 237202.
→Nature Asia-Pacificによる紹介記事 →科学新聞の紹介記事
→SPring-8からのプレスリリース
Charge transfer and dd excitations in transition metal oxides: q-dependent
dielectric function study by inelastic X-ray scattering and optical reflectivity
measurements
N. Hiraoka, H. Okamura, H. Ishii, I. Jarrige, K. D. Tsuei, and Y. Q. Cai
Eur. Phys. J. B 70 (2009) 157.
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Combining photoemission and optical spectroscopies for Reliable Valence Determination in YbS and Yb Metal
M. Matsunami, A. Chainani, M. Taguchi, R. Eguchi, Y. Ishida, Y. Takata,
H. Okamura, T. Nanba, M. Yabashi, K. Tamasaku, Y. Nishino, T. Ishikawa,
Y. Senba, H. Ohashi, N. Tsujii, A. Ochiai, S. Shin
Phys. Rev. B
78, 195118 (2008). (Editors' Suggestionに選ばれました)
Universal scaling in the dynamical conductivity of heavy fermion Ce
and Yb compounds
H. Okamura, T. Watanabe, M. Matsunami, N. Tsujii, T. Ebihara, H.
Sugawara, H. Sato, Y. Onuki, Y. Isikakwa, T. Takabatake, T. Nanba
J. Phys. Soc. Jpn.
76, 023703 (2007). (注目論文に選ばれました)
→JPSJ Onlineの"News
and Comments"による紹介 →科学新聞での紹介記事
Infrared study of valence transition compound YbInCu4
using cleaved surfaces
H. Okamura, T. Michizawa, T. Nanba, T. Ebihara
Phys. Rev. B
75 041101(R) (2007).
→SPring-8からの
プレスリリース →科学新聞での紹介記事
Photogenerated Carriers in SrTiO3 Probed by Mid-Infrared
Absorption
H. Okamura, M. Matsubara, K. Tanaka, K. Fukui, M. Terakami, H. Nakagawa,
Y. Ikemoto, T. Moriwaki, H. Kimura, T. Nanba
J. Phys. Soc. Jpn.
75 023703 (2006).
Photoinduced spin crossover in Fe-picolylamine complex: A
far-infrared study on single crystals
H. Okamura, M. Matsubara, T. Nanba, T. Tayagaki, S. Mouri, K. Tanaka, Y.
Ikemoto, T. Moriwaki, H. Kimura, G. Juhasz
Phys. Rev. B
72, 073108 (2005).
Indirect and direct energy gaps in Kondo semiconductor
YbB12
H. Okamura, T. Michizawa, T. Nanba, S. Kimura, F. Iga, T. Takabatake,
J. Phys. Soc. Jpn.
74, 1954 (2005)
Metal-insulator transition in PrRu4P12 and
SmRu4P12 investigated by optical spectroscopy.
M. Matsunami, L. Chen, M. Takimoto, H. Okamura, T. Nanba, C. Sekine,
I. Shirotani
Phys. Rev. B
72, 073105 (2005).
Carrier-induced magnetic circular dichroism in the magnetoresistive
pyrochlore Tl2Mn2O7.
H. Okamura, T. Koretsune, T. Nanba, S. Kimura, H. Imai, Y. Shimakawa,
Y. Kubo
J. Phys. Soc. Jpn.
74, 970 (2005)
Pseudogap formation and heavy-carrier dynamics in
intermediate-valence YbAl3
H. Okamura, T. Michizawa, T. Nanba, T. Ebihara
J. Phys. Soc. Jpn.
73, 2045 (2004).
Infrared study of spin-crossover Fe-picolylamine complex
H. Okamura, M. Matsubara, T. Tayagaki, K. Tanaka, Y. Ikemoto, H. Kimura,
T. Moriwaki, T. Nanba
J. Phys. Soc. Jpn.
73, 1355 (2004).
New Infrared and Terahertz Beamline BL6B at UVSOR
S. Kimura, E. Nakamura, J. Yamazaki, M. Katoh, T. Nishi, H. Okamura, M.
Matsunami, L. Chen and T. Nanba
AIP Conf. Proc. 705, 416-419 (2004).
Optical properties of filled skutterudites
CeT4Sb12 (T=Fe, Ru, Os)
M. Matsunami, H. Okamura, T. Nanba, H. Sugawara and H. Sato
J. Magn. Magn. Mater. 272-276, e41 (2004).
Modification of vibrational selection rules in the photo-induced
spin-crossover phase
T. Tayagaki, K. Tanaka, H. Okamura
Phys. Rev. B
69, 064104 (2004).
Gap formation in the filled Skutterudite
CeOs4Sb12
M. Matsunami, H. Okamura, T. Nanba, H. Sugawara, H. Sato
J. Phys. Soc. Jpn.
72, 2722 (2003).
Charge dynamics in the colossal magnetoresistance pyrochlore
Tl2Mn2O7
H. Okamura, T. Koretsune, M. Matsunami, S. Kimura, T. Nanba, H. Imai, Y.
Shimakawa, Y. Kubo
Phys. Rev. B
64,180409(R) (2001).
Infrared beamline at SPring-8: design and commissioning
H. Kimura, T. Moriwaki, N. Takahashi H. Aoyagi, T. Matsushita, Y.
Ishizawa, M. Masaki, S. Ohishi, H. Okuma, T. Nanba, M. Sakurai, S.
Kimura, H. Okamura, N. Nakagawa, T. Takahashi, K. Fukui, K. Shinoda, Y.
Kondo, T. Sata, M. Okuno, M. Matsunami, R. Koyanagi and Y. Yoshimatsu
Nucl. Instr. Methods Phys. Res. A 467-468, 441 (2001).
Infrared experiments under laser excitations at SPring-8
H. Okamura, K. Fukui, M. Matsunami, K. Terakami, M. Koyanagi, T. Koretsune,
T. Moriwaki, H. Kimura, H. Nakagawa, Y. Kondo, T. Nanba
Nucl. Instr. Methods Phys. Res. A 467-468, 1465 (2001).
Performance of IR-VUV normal incidence monochromator beamline at
UVSOR
K. Fukui, H. Miura, H. Nakagawa, I. Shimoyama, K. Nakagawa, H. Okamura,
T. Nanba, M. Hasumoto, T. Kinoshita
Nucl. Instr. Methods Phys. Res. A 467-468, 601 (2001).
Optical conductivity of Yb1-xLuxB12:
Energy gap and mid-infrared peak in diluted Kondo semiconductors
H. Okamura, M. Matsunami, T. Inaoka, S. Kimura, T. Nanba, F. Iga,
S. Hiura, J. Klijn, T. Takabatake
Phys. Rev. B
62, R13265 (2000).
Pseudogap formation in the intermetallic compounds
(Fe1-xVx)3Al
H. Okamura, J. Kawahara, T. Nanba, S. Kimura, I. Shimoyama, K. Nakagawa,
K. Soda, U. Mizutani, Y. Nishino, M. Kato, K. Fukui, H. Miura, H.
Nakagawa,
Phys. Rev. Lett.
84, 3674 (2000).
Optical Conductivity of the Kondo insulator YbB12: Gap
formation and low-energy excitations,
H. Okamura, S. Kimura, H. Shinozaki, T. Nanba, F. Iga,
N. Shimizu and T. Takabatake:
Phys. Rev. B
58, R7496 (1998).
Upgraded Inrared Beamline at UVSOR,
M. Sakurai, H. Okamura, M. Watanabe, T. Nanba, S. Kimura,
and M. Kamada:
J. Synchrotron Rad. 5, 578 (1998).
Reconstruction of BL7B for UV,VIS and IR spectroscopy with a 3 m
normal-incidence monochromator.
K.Fukui, H.Nakagawa, I.Shimoyama, K.Nakagawa, H.Okamura, T.Nanba et al.
J.Synchrotron Rad. 5, 836-838 (1998).
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