Electron-paramagnetic-resonance measurements on the di-<001>-split interstitial center (R1) in diamond.
Electron-paramagnetic-resonance measurements on the di-<001>-split interstitial center (R1) in diamond.
复制标题
对金刚石中的二-<001>-分裂间隙中心 (R1) 进行电子顺磁共振测量。
DOI：
10.1103/physrevb.54.6988
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Banholzer
中科院分区：
文献类型：
--
作者：
Twitchen;Newton;Baker;Tucker;Anthony;Banholzer
电子顺磁共振（EPR）研究在电子辐照金刚石富含5%C13导致识别的双< 001>分裂间隙中心。正是同位素富集和随后对C13超精细卫星的观测，使该中心的结构在发现后30多年才得以确定。通过一个简单的分子轨道计算的C13超精细耦合分析表明，该中心可以被看作是一个由两个未成对电子组成的双自由基，每个电子主要位于不同碳原子上的非键合2p轨道。这些电子之间的交换相互作用导致自旋三重态基态，其与单重态激发态很好地分离。在EPR中观察到的零场分裂起源于偶极，与未成对电子的分布一起，表明具有非键2p轨道的碳原子分离约2.2 π。中心具有σ h对称性。通过室温辐射形成的二< 001>分裂间隙证实了间隙在此温度下是移动的。该中心的鉴定表明碳< 001>自间隙的分裂间隙构型，这是迄今为止无法直接检测的基本缺陷。
Electron-paramagnetic-resonance (EPR) studies in electron-irradiated diamond enriched with 5% C 13 have resulted in identification of the di-< 001>-split interstitial center. It is the isotopic enrichment and the consequent observation of C 13 hyperfine satellites that have permitted the structure to be determined more than 30 years after the discovery of the center. Analysis of the C 13 hyperfine couplings by a simple molecular orbital calculation shows that the center may be viewed as a biradical consisting of two unpaired electrons, each primarily localized in a nonbonding 2p orbital, on different carbon atoms. The exchange interaction between these electrons results in a spin-triplet ground state which is well separated from the singlet excited state. The zero-field splitting observed in EPR is dipolar in origin and, taken together with the distribution of the unpaired electron population, indicates that the carbon atoms with the nonbonding 2p orbitals are separated by about 2.2 Å. The center has σ h symmetry. Formation of the di-< 001>-split interstitial by room temperature irradiation confirms that the interstitial is mobile at this temperature. Identification of this center suggests a< 001>-split interstitial configuration for the carbon self-interstitial, a fundamental defect which has so far eluded direct detection.© 1996 The American Physical Society.