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: | 9-九月-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 |
顯示於類別: | 期刊論文 |