Terahertz plasmonics in ferroelectric-gated graphene

Inspired by recent advancement of ferroelectric-gated memories and transistors, we propose a design of ferroelectric-gated nanoplasmonic devices based on graphene sheets clamped in ferroelectric crystals. We show that the two-dimensional plasmons in graphene can strongly couple with the phonon-polaritons in ferroelectrics, leading to characteristic modal wavelength of the order of 100-200 nm at low temperature and low-THz frequencies albeit with an appreciable dissipation. By patterning the ferroelectrics into different domains, one can produce compact on-chip plasmonic waveguides, which exhibit negligible crosstalk even at 20 nm separation distance. Harnessing the memory effect of ferroelectrics, low-power operation can be achieved on these plasmonic waveguides.