Universal conductance fluctuations in three dimensional metallic single crystals of Si

In this paper we report the measurement of conductance fluctuations in 3D crystals of Si made metallic by heavy doping. (L/L-phi similar to 10(3), where L-phi is the phase coherence length.) Temperature and magnetic field dependence of noise strongly indicate the universal conductance fluctuations as a predominant source of the observed magnitude of noise. Conductance fluctuations 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 knowledge of the level of disorder enables us to calculate the change in conductance 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 higher than its theoretically expected value in 3D systems.