c-Axis Raman scattering spectra of MgB2: observation of a dirty-limit gap in the pi bands.
c-Axis Raman scattering spectra of MgB2: observation of a dirty-limit gap in the pi bands.
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MgB2 的 c 轴拉曼散射光谱：观察 pi 带中的脏限间隙。
DOI：
10.1103/physrevlett.90.207006
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发表时间：
2002
影响因子：
8.6
通讯作者：
A. Yamanaka
中科院分区：
文献类型：
--
作者：
J. Quilty;S. Lee;S. Tajima;A. Yamanaka
在 zz、xz 和 xx 偏振下测量厚 MgB2 单晶 ac 面的拉曼散射光谱。在 zz 和 xz 偏振中，在下面的 T(c) 连续谱中形成了 29 cm(-1) 附近的阈值，但没有看到断对峰，这与 xx 偏振中 100 cm(-1) 附近的尖锐断对峰形成鲜明对比。 zz 和 xz 光谱与脏超导体的拉曼散射一致，而 xx 光谱中的尖峰表明系统是干净的。光谱分析解决了这一矛盾，将较大和较小的带隙量值置于 sigma 和 pi 带中，并表明相对较强的杂质散射仅限于 pi 带。
Raman scattering spectra from the ac face of thick MgB2 single crystals were measured in zz, xz, and xx polarizations. In zz and xz polarizations a threshold at around 29 cm(-1) forms in the below T(c) continuum but no pair-breaking peak is seen, in contrast to the sharp pair-breaking peak at around 100 cm(-1) in xx polarization. The zz and xz spectra are consistent with Raman scattering from a dirty superconductor while the sharp peak in the xx spectra argues for a clean system. Analysis of the spectra resolves this contradiction, placing the larger and smaller gap magnitudes in the sigma and pi bands and indicating that relatively strong impurity scattering is restricted to the pi bands.