Temperature-dependent Raman study of a CeFeAsO0.9F0.1 superconductor: crystal field excitations, phonons and their coupling

被引：12

作者：

Kumar, Pradeep ^{[1
]}

Kumar, Anil ^{[2
]}

Saha, Surajit ^{[1
]}

Muthu, D. V. S. ^{[1
]}

Prakash, J. ^{[3
]}

Waghmare, U. V. ^{[2
]}

Ganguli, A. K. ^{[3
]}

Sood, A. K. ^{[1
]}

机构：

[1] Indian Inst Sci, Dept Phys, Bangalore 560012, Karnataka, India

[2] Jawaharlal Nehru Ctr Adv Sci Res, Theoret Sci Unit, Bangalore 560064, Karnataka, India

[3] Indian Inst Technol, Dept Chem, New Delhi 110016, India

来源：

JOURNAL OF PHYSICS-CONDENSED MATTER | 2010年 / 22卷 / 25期

关键词：

PSEUDOPOTENTIALS; SCATTERING;

D O I：

10.1088/0953-8984/22/25/255402

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

We report temperature-dependent Raman spectra of CeFeAsO0.9F0.1 from 4 to 300 K in the spectral range of 60-1800 cm(-1) and interpret them using estimates of phonon frequencies obtained from first-principles density functional calculations. We find evidence for strong coupling between the phonons and crystal field excitations; in particular the Ce3+ crystal field excitation at 432 cm(-1) couples strongly with the E-g oxygen vibration at 389 cm(-1). Below the superconducting transition temperature, the phonon mode near 280 cm(-1) shows softening, signaling its coupling with the superconducting gap. The ratio of the superconducting gap to T-c, thus estimated to be similar to 10, suggests CeFeAsO0.9F0.1 to be a strong coupling superconductor. In addition, two high frequency modes observed at 1342 and 1600 cm(-1) are attributed to electronic Raman scattering from the (x(2)-y(2)) to xz/yz d-orbitals of Fe.

引用

页数：7

共 50 条

[1] Is LaFeAsO1-xFx an electron-phonon superconductor?
Boeri, L.
Dolgov, O. V.
Golubov, A. A.
[J]. PHYSICAL REVIEW LETTERS, 2008, 101 (02)
[2] BOERI L, 2010, ARXIV10011943
[3] Cardona M., 2000, LIGHT SCATTERING SOL, VVII
[4] Doping dependence of the lattice dynamics in Ba(Fe1-xCox)2As2 studied by Raman spectroscopy
Chauviere, L.
Gallais, Y.
Cazayous, M.
Sacuto, A.
Measson, M. A.
Colson, D.
Forget, A.
[J]. PHYSICAL REVIEW B, 2009, 80 (09):
[5] Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO1-xFxFeAs
Chen, G. F.
Li, Z.
Wu, D.
Li, G.
Hu, W. Z.
Dong, J.
Zheng, P.
Luo, J. L.
Wang, N. L.
[J]. PHYSICAL REVIEW LETTERS, 2008, 100 (24)
[6] Superconductivity at 43 K in SmFeAsO1-xFx
Chen, X. H.
Wu, T.
Wu, G.
Liu, R. H.
Chen, H.
Fang, D. F.
[J]. NATURE, 2008, 453 (7196) : 761 - 762
[7] Chen XK, 2001, PHYS REV LETT, V87, DOI [10.1103/PhysRevLett.87.157002, 10.1103/PhysRevLett.87.012001]
[8] Crystalline Electric Field as a Probe for Long-Range Antiferromagnetic Order and Superconducting State of CeFeAsO1-xFx
Chi, Songxue
Adroja, D. T.
Guidi, T.
Bewley, R.
Li, Shiliang
Zhao, Jun
Lynn, J. W.
Brown, C. M.
Qiu, Y.
Chen, G. F.
Lou, J. L.
Wang, N. L.
Dai, Pengcheng
[J]. PHYSICAL REVIEW LETTERS, 2008, 101 (21)
[9] Lattice and electronic anomalies of CaFe2As2 studied by Raman spectroscopy
Choi, K. -Y.
Wulferding, D.
Lemmens, P.
Ni, N.
Bud'ko, S. L.
Canfield, P. C.
[J]. PHYSICAL REVIEW B, 2008, 78 (21):
[10] Self-energy effects and electron-phonon coupling in Fe-As superconductors
Choi, K-Y
Lemmens, P.
Eremin, I.
Zwicknagl, G.
Berger, H.
Sun, G. L.
Sun, D. L.
Lin, C. T.
[J]. JOURNAL OF PHYSICS-CONDENSED MATTER, 2010, 22 (11)

← 1 2 3 4 5 →