Uniaxial-stress effects on the magnetic properties of Si:P close to the metal-non-metal transition

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Abstract
A sample of Si:P with a doping density n such that (n/nc)=0.85 at zero stress, where nc is the critical density for the metal-non-metal transition, has been studied at temperatures ranging from 15 mK up to 4.2 K using electron spin resonance techniques at very low magnetic fields. Some results have been obtained with uniaxial stress applied up to 0.2 GPa, implying a stress-tuning effect moving (n/nc) close to 0.9. The results indicate that the ESR linewidth and the electron spin susceptibility are proportional to one another when the temperature is varied at zero stress, that the susceptibility shows no sign of 'flattening off' at low temperature and that, within experimental error, there is no effect of stress on the magnetic susceptibility in this sample. The effect of stress on the linewidth is also anomalously small. The electrons appear to behave more like a metallic system than previous studies in Si:P in this density regime have demonstrated.