Local Structure about Defect Atoms in Crystals

晶体中缺陷原子的局域结构

• 批准号: 8907105
• 负责人: Frank Bridges
• 金额: $ 5万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-05-15 至 1992-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8907105&HistoricalAwards=false
• 关键词: Local; Structure; about; Defect; Atoms

Investigations of the local structure about defect atoms in several lightly doped materials with the emphasis on the continued study of off-center systems and the conditions for off- center behavior. The paraelectric-paraelastic tunneling centers represent ideal test systems for understanding low temperature tunneling behavior. Paraelectric resonance, dielectric constant measurements, and Extended X-ray Absorption Fine Structure (EXAFS) studies will be made on systems such as KCL with substitutional Li ions, NaBr with substitutional F ions, and KI with substitutional Ag ions as a function of hydrostatic pressure. Pressure moves the off-center defects back on center and leads to information relating to the conditions for the off- center displacement. It is also hoped to study off-center defects at much higher concentrations above the solubility limits as a function of temperature. It is hoped this work will have some connection to tunneling behavior in glasses.

研究了几种轻掺杂材料中缺陷原子的局域结构，重点是偏心系统的继续研究和偏心行为的条件。顺电-顺弹性隧道中心是了解低温隧道行为的理想测试系统。顺电共振、介电常数测量和扩展X射线吸收精细结构(EXAFS)研究将作为静水压力的函数，对含Li离子的KCL、含F离子的NaBrR和含Ag离子的KI等体系进行研究。压力将偏离中心的缺陷移回中心，并导致与偏离中心位移的条件有关的信息。它还希望研究高于溶解度极限的高得多浓度的偏心缺陷作为温度的函数。人们希望这项研究将与眼镜中的隧道行为有一定的联系。