2007 Fiscal Year Final Research Report Summary
Theoretical study on resonant x-ray scattering from the multipolar ordering phase
| Project/Area Number |
18540309
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Gunma University |
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Principal Investigator |
NAGAO Tatsuya Gunma University, Graduate School of Engineering, Associate professor (00237497)
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| Project Period (FY) |
2006 – 2007
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| Keywords | resonant x-ray scattering / multipole order / multipole transition / inelastic scattering / two magnon excitation |
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| Research Abstract |
We have derived useful expressions. Of the resonant x-ray scattering (RXS) amplitude on the basis of the localized electron picture. The expressions include precise energy dependence of the spectra since the summation over the intermediate states are carried out without using the so-called fast collision approximation with the assumption that the Hamiltonian describing the intermediate states preserves the rotational invariance. The expressions and their derivatives have proved that the spectral analysis in RXS in the felectron system can lend a powerful support in elucidating the nature of the multipolar ordering phases. We present some examples to show them.
First, we have applied to the multipolar ordering phases such as octupolar in Ce_<1-x>La_xB_6 and some other multi-k ordering phases. They reproduced the experimental results well and predicted some intriguing features.
Second, the expression has been extended to the case of the long period ordered structure such as the helical and conical magnetic phases exhibited by some heavy rare earth metal. Taking holmium as an example, we have calculated the RXS spectra. The results indicate that the spectral shape can discriminate the different phases in some cases in this system. We also have predicted that the fourth satellite spot is detectable in the electric dipole (E1) transition in the conical phase of Ho.
Third, RXS spectrum in the magnetite has been studied at the A site Fe ions, which lack local space inversion symmetry. Then, parity odd process, for instance, E1-quadrupole (E2) process survives when some specific experimental conditions are satisfied. We have calculated both the RXS and absorption spectra, the latter of which show clear evidence of the El-E2 process.
Finally, we have investigated two-magnon excitation spectra of resonant inelastic x- ray scattering from La_2CuO_4, which proves that the experimentally observed spectra are indeed due to the two-magnon excitations in cuprates.
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[Presentation] 共鳴非弾性x線散乱によるLa_2CuO_4の2マグノン励起の理論2006
Author(s)
長尾 辰哉、五十嵐 潤一
Organizer
The 1st International Symposium of Quantum Beam Science Directorate of JAEA
Place of Presentation
Techno Community Square Ricotti, Ibaraki
Year and Date
2006-08-29
Description
「研究成果報告書概要(和文)」より
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