Suppression of 1/f noise in graphene due to anisotropic mobility fluctuations induced by impurity motion

Low-frequency (1/f) noise is an intrinsic feature present in a wide variety of systems and efforts have been directed towards understanding its origin. Here, the authors use a suspended graphene Corbino device to investigate the sources of 1/f noise, presenting evidence to show that mobility fluctuations are an essential contributing factor. Low frequency resistance variations due to mobility fluctuations is one of the key factors of 1/f noise in metallic conductors. According to theory, such noise in a two-dimensional (2D) device can be suppressed to zero at small magnetic fields, implying important technological benefits for low noise 2D devices. In this work, we provide evidence of anisotropic mobility fluctuations by demonstrating a strong field-induced suppression of noise in a high-mobility graphene Corbino disk, even though the device displays only a tiny amount of 1/f noise inherently. The suppression of the 1/f noise depends on charge density, showing less non-uniform mobility fluctuations away from the Dirac point with charge puddles. We model our results using an approach based on impurity clustering dynamics and find our results consistent with the 1/f noise induced by scattering of carriers on mobile impurities forming clusters.