New electron spin resonance spectra from iron―vacancy pair in silicon: II. Hyperfine interactions and isotopic effect

摘要

We studied the TU2 and TU3 ESR spectra from an iron―vacancy pair in iron-doped and electron-irradiated float-zone grown silicon samples. Isotopic shifts in the fine structure term and hyperfine and superhyperfine interaction terms of the spin Hamiltonian are considered in detail. We obtained that the change in the spin value of the defect is accompanied by a modification of the iron atom position. The existing model fails to explain observed large anisotropy of the isotopic effect.