Ab Initio Study of the Dynamical Si-O Bond Breaking Event in α-Quartz

• 来源期刊: 中国物理快报（英文版）
• 关键词: @@
• 年，卷（期）: 2015,（10）
• 页码范围: 130-133
• 页数: 4页
• 语种: 中文
• DOI: 10.1088/0256-307X/32/10/107803

摘要

The Si-O bond breaking event in the α-quartz at the first triplet (T1) excitation state is studied by using ab initio molecular dynamics (AIMD) and nudged elastic band calculations.A meta-stable non-bridging oxygen hole center and E' center (NBOHC-E') is observed in the AIMD which consists of a broken Si-O bond with a Si-O distance of 2.54A.By disallowing the re-bonding of the Si and O atoms,another defect configuration (ⅢSi/V-Si) is obtained and validated to be stable at both ground and excitation states.The NBOHC-E' is found to present on the minimal energy pathway of the initial to Ⅲ-Si/V-Si transition,showing that the generating of the NBOHC-E' is an important step of the excitation induced structure defect.The energy barriers to produce the NBOHC-E' and Ⅲ-Si/V-Si defects are calculated to be 1.19 and 1.28eV,respectively.The electronic structures of the two defects are calculated by the self-consistent GW calculations and the results show a clear electron transition from the bonding orbital to the non-bonding orbital.