Fractional-flux Little-Parks resistance oscillations in disordered superconducting Au_(0.7)In_(0.3) cylinders

Resistance of disordered superconducting Au$_{0.7}$In$_{0.3}$ cylindrical films was measured as a function of applied magnetic field. In the high-temperature part of the superconducting transition regime, the resistance oscillated with a period of $h/2e$ in the unit of the enclosed magnetic flux. However, at lower temperatures, the resistance peaks split. We argue that this splitting is due to the emergence of an oscillation with a period of $h/4e$, half of the flux quantum for paired electrons. The possible physical origin of the $h/4e$ resistance oscillation is discussed in the context of new minima in the free energy of a disordered superconducting cylinder.