标题：Modification of RbTiOPO4(001) crystal surface induced by Ar+ion bombardment: X-ray photoelectron spectroscopy and first-principles studies
作者：Duan, Xiulan ;Liu, Jian ;Chen, Yang ;Li, Ziqing ;Zhu, Pengfei ;Jiang, Huaidong
作者机构：[Duan, Xiulan ;Liu, Jian ;Chen, Yang ;Li, Ziqing ;Zhu, Pengfei ;Jiang, Huaidong ] State Key Laboratory of Crystal Materials, Institute of Crystal Mate 更多
摘要：The (001) crystal surface of RbTiOPO4(RTP) were bombarded by Ar+ion during different times (2–20 min) and the resulting chemical modification on surface has been studied by X-ray photoelectron spectroscopy (XPS) and first-principles calculations. Ion bombardment can lead to great structural modification on the surface of RTP crystal. Reduction of Ti4+ions to the lower valence state (Ti3+) and formation of oxygen vacancies occur with Ar+ion irradiation. With the increase of irradiation time, proportion of reduced Ti3+ions and number of oxygen vacancies increase accordingly. Fraction of oxygen in P-O-Ti bonds decreases with increasing oxygen vacancies after bombardment for 5–20 min. We think that oxygen vacancies come from breaking of P-O-Ti bonds. The results were also confirmed theoretically by first-principles calculations. Existence of oxygen vacancies is also confirmed by absorption spectra. Formation of Ti3+state can be ascribed to the loss of surrounding oxygen caused by Ar+ion irradiation. This work helps us to better understand the ion-beam interaction with RTP surfaces.
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