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

Research Project

Project/Area Number	06402010
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Research Field	固体物性Ⅰ(光物性・半導体・誘電体)
Research Institution	KOBE UNIVERSITY
Principal Investigator	NANBA Takao FACULTY OF SCIENCE,KOBE UNIVERSITY PROFESSOR, 理学部, 教授 (30091721)
Co-Investigator(Kenkyū-buntansha)	OKAMURA Hidekazu FACULTY OF SCIENCE,KOBE UNIVERSITY ASSISTANT, 理学部, 助手 (00273756) OHTA Hitoshi FACULTY OF SCIENCE,KOBE UNIVERSITY ASSOCIATE PROFESSOR, 理学部, 助教授 (70194173)
Project Period (FY)	1994 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥29,700,000 (Direct Cost: ¥29,700,000) Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000) Fiscal Year 1995: ¥12,200,000 (Direct Cost: ¥12,200,000) Fiscal Year 1994: ¥16,400,000 (Direct Cost: ¥16,400,000)
Keywords	Kondo insulator / energy gap / CeRhSb / CeNiSn / 電子相関
Research Abstract	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.