Probing interactions in graphene through global and local current noise measurements

Electron-electron scattering plays an important role in graphene transport, and can even be the dominant scattering mechanism. This gives rise to a wealth of interesting collective phenomena, such as electron hydrodynamic behavior. Since e-e interactions inevitably affect current-current correlations, we can probe interactions by measuring current noise. I will present our recent observation of anomalous current fluctuations in biased graphene, using both global and local measurement techniques. Our electronic (global) noise measurements show not only an unexpected dependence on doping and bath temperature, but also a distinct noise spectrum. While this measurement provides a global spatial average of the noise, we also use nitrogen vacancy centers in diamond to probe the noise locally. The results from both measurements are incompatible with typical noise sources, and point to an unusual origin.