Structural and photoemission investigations of a new pseudo binary semimagnetic semiconductor: Sn_1−xMn_xSe₂

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• 作者：Mirabella ; F. ; Schmerber ; G. ; Golacki ; Z. ; Johnson ; R.L. ; Ghijsen ; J.
• 关键词：Magnetic semiconductor ; X-ray spectroscopy tin ; Selenium ; Manganese
• 刊名：Materials Science and Engineering ; B
• 出版年：2004
• 期刊代码：76_09215107
• 类别：ch
• 出版时间：July 15, 2004
• 卷：110
• 期：2
• 页码：143-151
• 文件大小：294 K

摘要

Sn_1−xMn_xSe₂ crystals have been grown by a modified Bridgman method aiming to form a new semimagnetic semiconductor whose particularity will be to have a layered CdI₂-type crystal structure. This paper reports the first detailed structural and photoemission study of this new material. X-ray diffraction analysis performed on two different samples showed that only one had the expected lattice symmetry, the other one being a mixture of SnSe and α-MnSe phases. Although the preparation method of these specimen was the same they differed by the manganese quantity inserted to substitute tin in the SnSe₂ lattice. This study also reveals that Mn-solubility into this lattice is not high. Photoelectron spectroscopy using X-ray and synchrotron radiation were also carried on. As it was expected, chemical states of tin and selenium in layered Sn_1−xMn_xSe₂ are Sn⁴⁺ and Se²⁻, respectively. Manganese is present as Mn²⁺ ion, like it is the case in II_1−xMn_xVI materials. Investigations of layered Sn_1−xMn_xSe₂ valence band revealed that the Mn 3d density of states is constituted of localized states at 3.5eV of binding energy with delocalized states at lower and higher energy. Differences in Mn 3d density of states have been observed with respect to a biphased Sn_1−xMn_xSe₂ compound.