Universal Conductance Fluctuation Due to Development of Weak Localization in Monolayer Graphene

The relationship between two quantum interference effects, the universal conductance fluctuation (UCF) and the weak localization (WL), is investigated in monolayer graphene. We find that the local maxima in the UCF as a function of the gate voltage (Fermi energy) show stronger WL resistivity correction. By comparing experimental results with the predictions of the WL theory, we find that the ratio of the inelastic dephasing length to the elastic intervalley scattering length varies in accordance with the UCF. Furthermore, the temperature dependence of the UCF amplitude is also well described by the theory of WL resistivity correction. Therefore, we propose that the UCF can be attributed to the WL in graphene. In addition, we investigate the UCF in the presence of the magnetic field perpendicular to the graphene sheet. Our fast Fourier transform analysis of the magnetic field dependence of the UCF reveals a length scale that is related to the phase shift caused by the Aharonov-Bohm effect. We discuss the relationship between this effective length and the elastic scattering lengths.