SAKURAI Junji Toyama Univ. Facul. of Sci. Professor, 理学部, 教授 (30033814)
OHTA Toshiaki Univ. of Tokyo, Facul. of Sci. Professor, 理学部, 教授 (80011675)
TOBIYAMA Makoto Hiroshima Univ. Facul. of Sci. Research Associate, 理学部, 助手 (60207595)
YOKOYAMA Toshihiko Hiroshima Univ. Facul. of Sci. Research Associate, 理学部, 助手 (20200917)
|Budget Amount *help
¥6,600,000 (Direct Cost : ¥6,600,000)
Fiscal Year 1992 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1991 : ¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1990 : ¥4,500,000 (Direct Cost : ¥4,500,000)
Aim of the present study is to obtain information on unoccupied conduction bands of Cd_<1-x>Mn_xY(Y=S,Se,Te) using inverse photoemission spectroscopy (IPES) and to reveal a whole electronic structure from a combination of new IPES and previous photoemission spectra.
IPES spectra are measured by monitoring intensity of the emitted ultraviolet photon-flux as a function of incident electron energy of 1-10 muA. On the other hand, since the resistivity of Cd_<1-x>Mn_xY(Y=S,Se,Te) is -100 MOMEGA, charging effect takes place and, thus, makes measurements difficult. One can avoid such a problem using thin film single crystals of Cd_<1-x>Mn_xY(Y=S,Se,Te). 1990:(1)To prepare thin film single crystals of Cd_<1-x>Mn_xY(Y=S,Se,Te), an appratus of hot wall epitaxy was designed and installed. (2)An ultrahigh vacuum chamber, in which the apparatus is placed, was made. This chamber was used as a sample preparation chamber for the IPES measurements.1991:(1)Cd_<1-x>Mn_xTe samples with -100 A thickness were grown in the preparation chamber. (2)IPES spectra of Cd_<1-x>Mn_xTe samples were successfully obtained. 1992:(1)Dependence of the IPES spectra of Cd_<1-x>Mn_xTe on the Mn concentration was systematically investigated and analyzed in detail. (2)Combination of photoemission and IPES spectra revealed a whole electronic structure of Cd_<1-x>Mn_xTe. In addition, the Mn 3d spin-exchange splitting energy was accurately determined to be 7.1*0.2 eV for the first time.
Mayor part of the initial purpose has been achieved. The present work will be extended to other Cd_<1-x>Mn_xY(Y=S,Se,Te) alloys.