title: Intrinsic defects and their effects on the optical properties in the nonlinear optical crystal CdSiP2: a first-principles study.
abstract: In view of their high nonlinear optical coefficients and good phase-matching properties, CdSiP2(CSP) crystals are considered as one of the most promising materials in the field of nonlinear optical applications. However, the slight absorption losses around 1.34 μm and 1.78 μm under e-polarized light have been affecting its performance. In this study, first-principles calculations were performed to identify the effects of various charge defects on the absorption properties. Different intrinsic defects in the CSP crystal were calculated using the HSE method and compared according to the specific chemical environments in the experiments. The results show that the point defects of V, Si, and V, which can be spontaneously formed, are dominant in the Cd-poor environment. The combination of Si and V defects is the most favorable cluster in the Cd-poor case because of its relatively low formation energy. Furthermore, the antisite defect SiCdwas found to be responsible for the main absorption peaks at 1.34 and 1.78 μm in the experimental spectra, whereas other defects and clusters, such as the defects Si and V, also contribute to these red shifted absorptions. Our results intend to provide a guideline for adjusting the optical absorption in CSP by modifying its defects.
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. jian.zhang@sdu.edu.cn txt@sdu.edu.cn.
authors.forename: Ci
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. jian.zhang@sdu.edu.cn txt@sdu.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.affiliation: Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004, China.
authors.forename: Huiyang
authors.initials: H
authors.lastname: Gou
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. jian.zhang@sdu.edu.cn txt@sdu.edu.cn.
authors.forename: Shanpeng
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. jian.zhang@sdu.edu.cn txt@sdu.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China. jian.zhang@sdu.edu.cn txt@sdu.edu.cn.
authors.forename: Xutang
authors.identifier: http://orcid.org/0000-0001-7664-7503
authors.initials: X
authors.lastname: Tao