Ultraviolet Photoemission and Inverse-Photoemission Spectroscopies of Diluted Magnetic Semiconductor Cd_<1-x>Mn_xTe

希薄磁性半導体Cd_<1-x>Mn_xTeの真空紫外光電子・逆光電子分光

三村 功次郎

Valence-band and conduction-band densities of states (DOS's) of Cd1-xMnxTe epitaxial films (0 ≤ x ≤ 0.7) have been investigated by means of in situ measurements of ultraviolet photoemission and inverse-photoemission spectroscopies (UPS and IPES).

Based on one-electron band theory, features observed at -3.4 and 3.6 eV relative to the valence-band maximum (VBM) are ascribed to emission from the Mn 3d↑ and 3d↓ states with eg symmetry, respectively, providing a Mn 3d spin-exchange splitting energy (Ueff) of 7.0±0.2 eV. This value compares well with the value predicted in the theoretical investigation of electronic structures and magnetic properties of Cd1-xMnxTe. With increasing Mn concentration, the energy position of the conduction-band minimum shifts almost linearly toward higher energy relative to the VBM as a result of an increasing contribution of the higher-lying Mn 4s level relative to the Cd 5s level.

Mn 3d partial DOS's in the valence-band region of Cd1-xMnxTe have been determined from resonant photoemission spectroscopy in the Mn 3p-3d core excitation region. The partial DOS's reveal an appreciable contribution of the Mn 3d states to the top 9 eV of valence bands with three structures; valence bands at 0~-2.5 eV, a main peak at -3.4 eV and a multielectron satellite at -5~-9 eV. These features are almost independent of the Mn concentration. Apart from one-electron band theory, the whole spectrum including the multielectron satellite is found to be well reproduced in terms of the configuration interaction theory using a Mn2+(Te2-)4 model cluster.

Electronic structures of zinc-blende MnTe epitaxial films have also been investigated by means of UPS and IPES. The Ueff-value of zinc-blende MnTe is in good agreement with those of Cd1-xMnxTe and Zn 1-xMnxTe. The width of valence bands and Ueff are by 1.3 eV narrower and by 0.3 eV larger than those of NiAs-type MnTe, respectively.

電気工学 [ 540 ]

英語

Copyright(c) by Author

(1)Mn 3d states of Cd1-xMnxTe (Cd1-xMnxTeのMn3d状態) 1冊, 共著者 三村功次郎、佐藤仁、原田次郎、宮崎圭司、谷口雅樹、植田義文, (学術誌) Journal of Magnetism and Magnetic Materials 140-144, 2017-2018 (1995). (ELSEVIER SCIENCE PUBLISHERS B.V) 1995年出版 ～を参照している

(2) Ultraviolet inverse-photoemission and photoemission spectroscopy studies of diluted magnetic semiconductors Cd1-xMnxTe (0≤x≤0.7) (希薄磁性半導体Cd1-xMnxTe(0≤x≤0.7)の真空紫外逆光電子・光電子分光による研究) 1冊, 共著者 谷口雅樹、三村功次郎、佐藤仁、原田次郎、宮崎圭司、生天目博文、植田義文, (学術誌) Physical Review B 51, 6932-6939 (1995). (THE AMERICAN PHYSICAL SOCIETY) 1995年3月15日出版 ～を参照している

(3) ULTRAVIOLET INVERSE-PHOTOEMISSION AND PHOTOEMISSION STUDIES OF DILUTED MAGNETIC SEMICONDUCTOR Cd1-xMnxTe (希薄磁性半導体Cd1-xMnxTeの真空紫外逆光電子・光電子分光による研究) 1冊, 共著者 谷口雅樹、三村功次郎、佐藤仁、生天目博文、植田義文, (学術誌) Proceedings of 22nd International Conference on the physics of Semiconductors (Vancouver) 3, 2565-2568 (1994). (World Scientific Publishing Co. Pte. Ltd.) 1995年出版 ～を参照している

(4)Ultraviolet inverse-photoemission and photoemission spectroscopies of zincblende MnTe (閃亜鉛鉱型MnTeの真空紫外逆光電子・光電子分光) 1冊, 共著者 三村功次郎、佐藤仁、仙波伸也、生天目博文、谷口雅樹, (学術誌) Physica B, in press. (ELSEVIER SCIENCE PUBLISHERS B.V.) 1997年出版予定 ～を参照している

[DOI] http://dx.doi.org/10.1016/0304-8853(94)00710-1 ～を参照している

[DOI] http://dx.doi.org/10.1103/PhysRevB.51.6932 ～を参照している

[DOI] http://dx.doi.org/10.1016/S0921-4526(97)00247-0 ～を参照している

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