First-principles study of cadmium vacancy in CdWO₄ crystal

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• 作者：Xiuwen Zhou ; Tingyu Liu ; Qiren Zhang ; Fang Cheng ; Hailing Qiao
• 关键词：CdWO₄ crystal ; Cadmium vacancy ; V_F center ; Optical properties
• 刊名：Solid State Sciences
• 出版年：2009
• 出版时间：December 2009
• 年：2009
• 卷：11
• 期：12
• 页码：2071-2074
• 全文大小：278 K

文摘

The structural relaxation, electronic structures and optical properties of CdWO₄ crystal containing cadmium vacancy (CWO:V_Cd) are studied by the CASTEP code. The cadmium vacancy (V_Cd) would trap two holes to maintain the local electrical neutrality. The calculated structural relaxation and electronic density of states reveals that the existent form of the hole in CWO:V_Cd should be oxygen molecular ion (O₂³⁻). Therefore an associated color center [O₂³⁻–V_Cd–O₂³⁻] named as V_F center would form in the crystal. The calculated optical absorption spectrum for CWO:V_Cd indicates that this V_F center would cause an absorption band peaking at about 650 nm with a shoulder at around 400 nm, which is in agreement with the experimental optical absorptions of the blue–grey colored CWO crystal.