Conductance fluctuations near the Anderson transition

In this letter we report measurements of conductance fluctuations in single-crystal samples of Si doped with P and B close to the critical composition of the metal-insulator transition . The measurements show that the noise, which arises from bulk sources, does not diverge as the Ioffe-Regal limit (k_F l1) is approached from the metallic side. At room temperature, the magnitude of the noise shows a shallow maximum at around k_F l1.5 and drops sharply as the insulating state is approached.