Tight binding calculations for the environmental dependence of the dangling bond g-factor in a-Si

The environmental (or strain) dependence of the electron spin resonancegtensor is calculated for a-Si using a tight binding model of a dangling bond with Bethe lattice back bonding. We find that the variations ofg∥andg⊥are almost identical and we obtain a value ofg∥− g⊥= 0.0025which is considerably smaller than the value for thePbcenter at the Si/SiO2interface. We obtain a good fit to experimental data assuming only a Gaussian distribution of bond angles with an rms deviation of about 9°, which is the generally accepted value for bond angle distortions at tetrahedral sites in a-Si.