  The versatile control of graphene's plasmonic modes via an external
gate-voltage inspires us to design efficient electro-optical graphene plasmonic
logic gates at the midinfrared wavelengths. We show that these devices are
superior to the conventional optical logic gates because the former possess
cut-off states and interferometric effects. Moreover, the designed six basic
logic gates (i.e., NOR/AND, NAND/OR, XNOR/XOR) achieved not only ultracompact
size lengths of less than {\lambda}/28 with respect to the operating wavelength
of 10 {\mu}m, but also a minimum extinction ratio as high as 15 dB. These
graphene plasmonic logic gates are potential building blocks for future
nanoscale midinfrared photonic integrated circuits.
