Raman and Other Optical Properties of Superconductors

高度相关的f电子金属，特别是那些表现出重费米子行为的金属，将构成这个项目的主要推动力。重点将放在f电子原子与其环境的耦合如何影响光学性质和光散射。当发现拉曼活动模的强度随着重费米子态的逐渐开始而增加时，将使用磁场来抑制开始，并观察到光谱中的影响。我们将研究磁序状态中的波和磁激发。通过测量压力下的拉曼光谱，可以利用强电子格吕内森效应。拉曼结果将与已知的弹性常数结果和将利用布里渊散射获得的新结果相关联。将对新的高T_c超导体进行拉曼光谱和光学性质测量。重点是表面处理的影响，特别是氧含量的控制对光谱的影响。结构扭曲的作用将通过拉曼布里渊散射测量来阐明。将与合作者所做的超导和结构测量进行关联。

Highly-correlated f-electron metals, especially those that show heavy Fermion behavior, will form the main thrust of this project. Emphasis will be on how the coupling of the f-electron atom to its environment affects optical properties and light scattering. When Raman-active modes are found whose intensity, as with URu2Si2, increases upon the gradual onset of the heavy- Fermion state, a magnetic field will be used to suppress the onset and the effect in the spectra will be observed. Waves in magnetically-ordered states and magnetic excitations will be studied. The strong electronic Gruneisen effect will be exploited by measuring Raman spectra under pressure. The Raman results will be correlated with known elastic constant results and new ones to be obtained using Brillouin scattering. Raman and optical-property measurements will be made on the new high Tc superconductors. Emphasis will be placed on the effects of surface treatment, especially control of oxygen content on the spectra. The role of structural distortions will be elucidated by Raman Brillouin scattering measurements. Correlations will be made with superconducting and structural measurements made by collaborators.