The effect of diffusive trajectories on conductance fluctuations in ballistic point contacts

Abstract

We have measured the non-universal conductance fluctuations (CFs) in Au and Au 1− x Pd x point contacts for a wide range of the degree of disorder. The scaling behaviour of the amplitude and the magnetic field scale of the CFs known for highly ballistic contacts breaks down as the scaling parameter a/ l e is increased from 0.03 to 0.35. This arises from diffusive remote trajectories backscattered to the constriction, which modify the properties of the CFs and the correlation function. A new formula for the derivative of the correlation function is obeyed by our experimental data.