1. f 電子系超伝導体の軟X線放射光分光 共同研究者 藤森 淳 （東大新領域、原研放射光）
“放射光を利用した物性科学の発展と展望” 研究会
原研放射光科学研究センター、2004年3月18-19日　
藤森　淳 （東大新領域、原研放射光）
共同研究者
藤森伸一、斎藤祐児、岡根哲夫、岡本淳、中谷健、村松康司（原研放射光）
間宮一敏（KEK－PF）
島田賢也、成村孝正、小林賢一、生天目博文、谷口雅樹（広島大放射光）
池田修悟、青木 大、宍戸寛明（阪大理）
芳賀芳範、山本悦嗣、松田達麿（原研先端研）
大貫惇睦（阪大理、原研先端研）
山上浩志、常盤欣文（京都産業大）、播磨尚朝（阪大産研）
田中 新（広島大先端物質）

2. Outline JAERI beamline BL-23SU Ce and U exotic superconductors PES MCD
Ce115 compounds: superconductivity near QCP
U115 compounds
Ferromagnetic superconductor UGe2
Antiferromagnetic superconductor UPd2Al3

3. Beamlines in Spring-8
RI samples
(U compounds)

4. JAERI beamline BL-23SU of Spring-8
Y. Saitoh et al., Nucl. Instrum. Methods A ’01.

5. JAERI beamline BL-23SU of Spring-8
Y. Saitoh et al., Rev. Sci. Instrum. ’ 00

6. JAERI beamline BL-23SU of Spring-8
ARPES装置
MCD装置
MCD　
PES　
Synchrotron Radiation
PES station
　　Scienta 2002, Gammadata VUV5000
MCD station
　　Superconducting magnet, up to 10 T
　　Low temperature, down to 10 K
U compounds can be measured

7. Resonant photoemission
S.I. Fujimori et al

8. Resonant photoemission
K. Shimada et al.
A. Sekiyama et al., Nature ‘00.

9. Angle-resolved photoemission (ARPES)

10. MCD in core-level x-ray absorption from metal 2p core level
spin sum rule
Apple II-type
helical undulator
orbital sum rule
Element-selective magnetic probe
A1 - A2
　　Superconducting magnet, up to 10 T
　　Low temperature, down to 10 K

11. Outline JAERI beamline BL-23SU Ce and U exotic superconductors PES MCD
Ce115 compounds: superconductivity near QCP
U115 compounds
Ferromagnetic superconductor UGe2
Antiferromagnetic superconductor UPd2Al3

12. Superconductivity near quantum critical point
Doniach’s phase diagram
Non-Fermi liquid
superconducting
Antferromagnetic metal
Fermi liquid
quantum
critical point
S. Doniach
G.G. Lonzarich

13. Quasi-2D superconductors near quantum critical point CeTIn5 (T=Rh, Ir, Co)
antiferromagnetic
Rh, Ir
supercond. Ce
Superconductivity at ambient pressure
in CeIrIn5 (TC = 0.4 K) and CeCoIn5 (TC = 2.2 K)
H. Hegger et al. PRL ‘00
H. Shishido et al. PRB ‘02

14. Quasi-2D superconductors near quantum critical point CeTIn5 (T=Rh, Ir, Co)
pressure
H. Shishido et al. JPSJ 02
Doniach’s phase diagram
CeRhIn5
CeIrIn5
CeCoIn5
Non-Fermi liquid
superconducting
Antferromagnetic metal
Fermi liquid
quantum
critical point
S. Doniach
G.G. Lonzarich

15. Resonant photoemission and XAS
Ce 4d-4f
@ Hi-SOR
Ce 3d-4f
Ce 3d XAS
@ Spring-8
spin-orbit
sideband
nf ~ 1
S.I. Fujimori et al., PRB ‘03
S.I. Fujimori et al., Physica C ‘03

16. CeRhIn5: AREPS and band-structure calculations
hn = 21.2 eV
S.I. Fujimori et al., PRB ‘03
Band calc: H. Harima

17. CeIrIn5: AREPS and band-structure calculations
hn = 21.2 eV
S.I. Fujimori et al., PRB ‘03
Band calc: H. Harima

18. ARPES Fermi surfaces in CeIrIn5
Fermi surface mapping
compared with LDA
Fermi surface of CeIrIn5
by LDA calculation
H. Harima A M
S.I. Fujimori et al., PRB ‘03

19. Hybridized spd-f band model
Ce compound
La compound Wf
f band
spd band

20. Hybridized spd-Ce 4f bands in CeIrIn5
He I (hn = 21.2 eV) → sp
4d-4f RPES (hn = 122 eV) → Ce 4f　
@ Hi-SOR
S.I. Fujimori et al.

21. Outline JAERI beamline BL-23SU Ce and U exotic superconductors PES MCD
Ce115 compounds: superconductivity near QCP
U115 compounds
Ferromagnetic superconductor UGe2
Antiferromagnetic superconductor UPd2Al3

22. Quasi-2D UTGa5 (T = Fe, Pt) UTGa5 UGa3 U Fe, Pt Ga Ga Fe, Pt U
UFeGa5 : paramagent
UPtGa5 : antiferromagnet (TＮ=26K)
cf) PuCoGa5: superconductor (TC=18.5K)

23. Photoemission spectra of UTGa5 (T = Fe, Pt)
U 5f
sensitivity PM
AFM
Fe 3d
U 5f
U 5f
S.I. Fujimori et al.

24. Band structure and Fermi surfaces of UFeGa5 wide 5f band
Fermi surface mapping
S.I. Fujimori et al.
Band calc: H. Yamagami

25. Photoemission spectra of UTGa5 (T = Fe, Pt)
U 5f
sensitivity PM
AFM
Fe 3d
U 5f
U 5f
S.I. Fujimori et al.

26. Band structure of UPtGa5 narrow 5f band
S.I. Fujimori et al.

27. Outline JAERI beamline BL-23SU Ce and U exotic superconductors PES MCD
Ce115 compounds: superconductivity near QCP
U115 compounds
Ferromagnetic superconductor UGe2
Antiferromagnetic superconductor UPd2Al3

28. Ferromagentic superconductor UGe2
ferromagnetic T*
new order parameter ?
supercond.
TCurie = 52 K
TSC = 0.8 GPa
T* ~ 30 K: anomaly ?
TCurie T*
S. S. Saxena et al., Nature ‘00
A. Huxley et al., PRB ‘01
N. Tateiwa et al., JPSJ ‘01

29. U M4,5 (3d  5f) MCD of U compoundsUS
Raw data (TFY method)
self-absorption effects
Corrected data
matrix-element effects ??
S.P. Collins et al.,
J. Phys. Cond. Mat. ‘95

30. U N4,5 (4d  5f) MCD of UGe2 -1.46 -1.52 2.98 LDA -2.24 -1.17 2.62 U3+
diffraction
-2.60
-0.91
2.37
U4+
Neutron
-1.9
-1.5
2.9
MCD (T=25K)
mL/mS mS mL
T. Okane et al.
Neutron: Keranvanois et al., PRB ‘01

31. U N3 (4p  6d), Ge L2,3 (2p  4s) MCD of UGe2
No polarization of U 6d electrons
Finite Ge L2,3 MCD Finite polarization of Ge 4s electrons
T. Okane et al.

32. U N4,5 (4d  5f) MCD of UGe2 -1.46 -1.52 2.98 LDA -2.24 -1.17 2.62 U3+
diffraction
-2.60
-0.91
2.37
U4+
Neutron
-1.9
-1.5
2.9
MCD (T=25K)
mL/mS mS mL
T. Okane et al.
Neutron: Keranvanois et al., PRB ‘01

33. U N4,5 MCD of UGe2 : Temperature dependence
TCurie
T. Okane et al.

34. Outline JAERI beamline BL-23SU Ce and U exotic superconductors PES MCD
Ce115 compounds: superconductivity near QCP
U115 compounds
Ferromagnetic superconductor UGe2
Antiferromagnetic superconductor UPd2Al3

35. Antiferromagentic superconductors
UPd2Al3
a = Å
c = Å
TN= 14K(0.85mB)
TC= 2 K
UNi2Al3
a = Å
c = Å
TN= 2.4K(0.24mB)
TC= 1 K
UPt3
a = Å
c = Å
TN= 5 K(0.02mB)
TC= 0.4 K
localized
itinerant
U 5f electrons

36. Photoemission spectra of UPd2Al3
S.I. Fujimori et al.

37. Conclusions Ce115 compounds: superconductivity near QCP U115 compounds
Ce 4f electrons are nearly localized, nf ~ 1.
but participates in band/Fermi surface formation in CeIrIn5.
U115 compounds
Different degrees of localization have been demonstrated between UFeGa5 and UPtGa5.
Ferromagnetic superconductor UGe2
Spin and orbital moments and their temperature dependence have been obtained by MCD
with no anomaly at ~T*
High (optimized) beamline performance has been achieved at BL-23SU.
Many scientific opportunities are foreseen.

38. Scientific opportunities at BL-23SU
U compounds
SX-AREPS, MCD, core-level XPS
Basic sciences of strong correlation
3-dimensional transition-metal oxides -- SX-ARPES
Ferromagnetic oxides -- MCD
Nano-sciences
Diluted magnetic semiconductors -- MCD at low-T, high-H
Oxide thin films, interfaces, nano-structures
Intercalation, nano-magnets, …..

39. Combined in situ PES-PLD systemSR
PES
CCD Cameras
cf. Oshima group at KEK-PF

40. Scientific opportunities at BL-23SU
U compounds
SX-AREPS, MCD, core-level XPS
Basic sciences of strong correlation
3-dimensional transition-metal oxides -- SX-ARPES
Ferromagnetic oxides -- MCD
Nano-sciences
Diluted magnetic semiconductors -- MCD at low-T, high-H
Oxide thin films, interfaces, nano-structures
Intercalation, nano-magnets, …..
New directions: Proposals are welcome !

41. 原研放射光・電子物性研究グループ
■研究テーマ "強相関電子系機能性材料の電子構造に関する研究" 超伝導や巨大磁気抵抗など特異な物性を示す遷移金属、希土類、ウランを含む強相関電子 系物質とこれらの物質を複合化、ナノ構造化した新しい機能を持つ物質・材料の化学結合状 態・電子構造を各種軟x線分光法を用いて明らかにする。得られた情報から物質設計・材料設 計の指針を得てIT、環境、エネルギーに関連した新材料の開発に資する。
■メンバー 安居院あかね / Akane Agui 岡根哲夫 / Tetsuo Okane 岡本淳 / Jun Okamoto　　博士研究員 斉藤祐児 / Yuji Saitoh 竹田幸治 / Yukiharu Takeda　　博士研究員 竹山雅義 / Masayoshi Takeyama　業務協力員 寺井恒太 / Kota Terai　　博士研究員 中谷健 / Takeshi Nakatani 藤森淳 / Atsushi Fujimori　　客員研究員 藤森伸一 / Shinichi Fujimori 村松康司 / Yasuji Muramatsu　　グループリーダー