日本原子力研究開発機構 (JAEA) / 量子ビーム応用研究部門
放射光科学研究ユニット / 放射光量子シミュレーショングループ
日時: | 平成19年 7月5日(木) 16:00〜 |
Date and time: | 5th July (Thu.) 16:00〜 |
場所: | SPring-8, 萌光館 |
Place: | SPring-8, "HOUKOUKAN" seminar room |
Title: | Electron Spin Resonance Intensity in Spin Dimer Systems |
講演者: | 松本正茂 氏 (静岡大学理学部物理) |
Speaker: | Prof. Masashige Matsumoto (Shizuoka University) |
Abstract: |
Electron spin resonance (ESR) is one of the most important experiments to study magnetic excitations. The development in high magnetic field experiments enables us to study magnetic field-induced ordering in quantum spin systems. Here we discuss interacting spin dimers [1,2]. The groundstate of TlCuCl3 is a spin-singlet liquid with only short-range correlations. The triplet excitations require a finite excitation energy from the spin-singlet groundstate. ESR experiments were performed in TlCuCl3 and KCuCl3 to reveal field dependence of magnetic excitations [3,4]. They observed transitions from the groundstate to excited states in both disordered and ordered phases. Sakai et al. studied the direct ESR transition theoretically taking Dzyaloshinskii-Moriya interactions into account [5]. We extend this type of study and investigate ESR intensity in both disordered and ordered phases applying a spin-wave theory described by bond operators, and elucidate effects of the Dzyaloshinskii-Moriya interaction on the ESR transition.
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