On the Possibility of Ultra-Low Power Switching in Multilayer Graphene Nanostructures

B. Dellabetta, J. Shumway, M.J. Gilbert
University of Illinois, US

Keywords: graphene, excitons, post-CMOS


A particularly attractive way to solve the power consumption problem in next generation logic devices is by harnessing collective motion of electrons. While collective phenomena are normally found at low temperatures, recent work suggests it possible to find spontaneous coherence at and above room temperature in closely spaced monolayers of graphene separated by a tunnel dielectric. This occurs when electrons in the top layer bind with vacancies in the bottom layer via a strong Coulomb interaction to form “indirect excitons”, which in turn organize into a Bose-Einstein condensate. This type of behavior may be viewed as spontaneous interlayer coherence: selection of a particular superposition of states in the two layers for the entire system. Despite the potential applications, the superfluid phase of bilayer graphene remains a poorly understood quantity. In this contribution, we theoretically examine the materials properties, length scales and transport conditions required to realize and manipulate this state at room temperature. Additionally, we present results of static and dynamic quantum Monte Carlo calculations detailing the ability of the exciton condensate to screen the additional fermion flavors found in graphene.