Physics (Internal)

Flexural phonon limited mobility in doped suspended graphene.

This event is part of the Condensed Matter Theory Seminar Series.

ABSTRACT:

The two-dimensional allotrope of carbon — graphene — has been
attracting considerable attention since the first flake was isolated
five years ago. The enormous interest is driven equally by the
unconventional low-energy behavior (massless Dirac quasiparticles) and
potential technological applications. Regarding the latter, the giant
intrinsic carrier mobility observed in suspended graphene (free of
substrate induced limitations) is certainly an asset. The reported big
numbers, however, show up only at low temperatures; at room
temperature mobility falls into the values reported for non-suspended
samples. In this talk I will explore the effect of flexural phonons —
out-of-plane vibrations of the graphene membrane — on the
resistivity’s temperature dependence of doped suspended graphene. It
will be shown that flexural acoustic phonons give the major scattering
contribution at room temperature, and indeed limit mobility to values
known for samples on substrate. A work around based on the possibility
of inducing strain to the graphene membrane will be discussed.