STUDY OF THE ELECTRONIC STRUCTURE OF STRONGLY CORRELATED ELECTRON SYSTEMS BY FAR-INFRARED AND MILLIMETER WAVES

在强关联电子系统中，CeNiSn和CeRhSbare被称为典型的近藤绝缘体，它们在费米能级附近具有非常小的能隙。为了进行这种研究，需要对电子结构进行光谱学研究。我们在低温下对这些材料进行了从毫米波到真空紫外线的非常宽的能量范围内的反射测量。同步辐射被用作光源。本研究取得了以下结果：（1）通过反射测量，得到了CeNiSn和CeRhSb的精确光学常数，讨论了光谱中结构的起源。(2)从低温下在远红外和毫米波区域对CeRhSb的反射测量中，我们发现反射率在3meV以下明显下降，这可能对应于差距的形成。(3)利用超导磁体在强磁场下完成了光谱系统的构建，使强关联电子系统的透射和反射测量成为可能。

Among strongly correlated electron system, CeNiSn and CeRhSbare known as a typical Kondo insulator which has a very small energy gap near the Fermi energy level. For such investigation, spectroscopic study on the electronic structure is required to perform.We performed a reflection measurement on these materials at low temperature in the very wide energy region from a millimeter wave to a vacuum ultraviolet region. The synchrotron radiation was used as a light source. In this study, the following results were obtained,(1) From the reflection measurement, we obtained the exact optical constans on CeNiSn and CeRhSb to discuss the origin of the structure in the spectrum.(2) From the reflection measurement on CeRhSb in the far-infrared and millimeter wave regions at low temperature, we found the clear decrease in the reflectivity below 3meV which presumably corresponds to the gap formation.(3) The complete construction of the spectroscopic system under high magnetic field using a superconducting magnet which makes possible measurements of a transmission and a reflection on a strongly correlated electron system.