Universal conductance fluctuations in three dimensional metallic single crystals of Si

In this paper we report the measurement of conductance fluctuations in 3D c rystals of Si made metallic by heavy doping. (L/L-phi similar to 10(3), whe re L-phi is the phase coherence length.) Temperature and magnetic field dep endence of noise strongly indicate the universal conductance fluctuations a s a predominant source of the observed magnitude of noise. Conductance fluc tuations within a single phase coherent region of L-phi(3) were found to be saturated at [(delta G(phi))(2)] approximate to (e(2)/h)(2). An accurate k nowledge of the level of disorder enables us to calculate the change in con ductance delta G(1) due to movement of a single scatterer as [(delta G(1))( 2)] similar to (e(2)/h)(2), which is similar to 2 orders of magnitude highe r than its theoretically expected value in 3D systems.