We report new measurements of the electrical conductivity $\sigma$ of the canonical three-dimensional metal-insulator system Si:P under uniaxial stress S. The zero-temperature extrapolation of $\sigma$(S,T$̊ightarrow$0)$\sim$|S-Sc|$\mu$ shows an unprecedently sharp onset of finite conductivity at Sc with an exponent $\mu$=1. The value of $\mu$ differs significantly from that of earlier stress-tuning results. Our data show dynamic $\sigma$(S,T) scaling on both metallic and insulating sides, viz. $\sigma$(S,T)=$\sigma$c(T)\textperiodcentered{}F$′$(|S-Sc|/Ty) where $\sigma$c(T) is the conductivity at the critical stress Sc. We find y=1/z$\nu$=0.34 where $\nu$ is the correlation-length exponent and z the dynamic critical exponent.     «

We report new measurements of the electrical conductivity $\sigma$ of the canonical three-dimensional metal-insulator system Si:P under uniaxial stress S. The zero-temperature extrapolation of $\sigma$(S,T$̊ightarrow$0)$\sim$|S-Sc|$\mu$ shows an unprecedently sharp onset of finite conductivity at Sc with an exponent $\mu$=1. The value of $\mu$ differs significantly from that of earlier stress-tuning results. Our data show dynamic $\sigma$(S,T) scaling on both metallic and insulating sides, viz....     »