標題: Pressure dependence of the electronic structure and spin state in Fe1.01Se superconductors probed by x-ray absorption and x-ray emission spectroscopy
作者: Chen, J. M.
Haw, S. C.
Lee, J. M.
Chou, T. L.
Chen, S. A.
Lu, K. T.
Liang, Y. C.
Lee, Y. C.
Hiraoka, N.
Ishii, H.
Tsuei, K. D.
Huang, Eugene
Yang, T. J.
電子物理學系
Department of Electrophysics
公開日期: 9-Sep-2011
摘要: Pressure dependence of electronic structures and spin states of iron-chalcogenide Fe1.01Se superconductors up to similar to 66 GPa has been investigated with x-ray emission spectra and x-ray absorption spectra with partial-fluorescence yield. The intensity of the pre-edge peak at energy of similar to 7112.7 eV of the Fe K-edge x-ray absorption spectrum of Fe1.01Se decreases progressively with pressure up to similar to 10 GPa. A new prepeak at energy of similar to 7113.7 eV develops for pressure above similar to 13 GPa, indicating formation of a new phase. The experimental and the calculated Fe K-edge absorption spectra of Fe1.01Se using the FDMNES code agree satisfactorily. The larger compression accompanied by significant distortion around the Fe atoms along the c axis in Fe1.01Se upon applying pressure suppresses the Fe 3d-Se 4p and Fe 4p-Se 4d hybridization. The applied pressure suppresses the nearest-neighbor ferromagnetic superexchange interaction and enhances spin fluctuations on the Fe sites in Fe1.01Se. A discontinuous variation of the integrated absolute difference values of the K beta emission line was observed, originating from a phase transition of Fe1.01Se for a pressure >12 GPa. Fe1.01Se shows a small net magnetic moment of Fe-2 broken vertical bar at ambient pressure, probably arising from strong Fe-Fe spin fluctuations. The satellite line K beta' was reduced in intensity upon applying pressure and became absent for pressure >52 GPa, indicating a continuous reduction of the spin moment of Fe in Fe1.01Se superconductors. The experimental results provide insight into the spin state of Fe1.01Se superconductors under pressure.
URI: http://dx.doi.org/10.1103/PhysRevB.84.125117
http://hdl.handle.net/11536/150367
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.84.125117
期刊: PHYSICAL REVIEW B
Volume: 84
Issue: 12
起始頁: 0
結束頁: 0
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