65 research outputs found
Proposal for a single-molecule field-effect transistor for phonons
We propose a practical realization of a field-effect transistor for phonons.
Our device is based on a single ionic polymeric molecule and it gives
modulations as large as -25% in the thermal conductance for feasible
temperatures and electric field magnitudes. Such effect can be achieved by
reversibly switching the acoustic torsion mode into an optical mode through the
coupling of an applied electric field to the dipole moments of the monomers.
This device can pave the way to the future development of phononics at the
nanoscale or molecular scale
Microscopic model of a phononic refrigerator
We analyze a simple microscopic model to pump heat from a cold to a hot
reservoir in a nanomechanical system. The model consists of a one-dimensional
chain of masses and springs coupled to a back gate through which a
time-dependent perturbation is applied. The action of the gate is to modulate
the coupling of the masses to a substrate via additional springs that introduce
a moving phononic barrier. We solve the problem numerically using
non-equilibrium Green function techniques. For low driving frequencies and for
sharp traveling barriers, we show that this microscopic model realizes a phonon
refrigerator.Comment: 9 pages, 4 figure
The role of the disorder range and electronic energy in the graphene nanoribbons perfect transmission
Numerical calculations based on the recursive Green's functions method in the
tight-binding approximation are performed to calculate the dimensionless
conductance in disordered graphene nanoribbons with Gaussian scatterers.
The influence of the transition from short- to long-ranged disorder on is
studied as well as its effects on the formation of a perfectly conducting
channel. We also investigate the dependence of electronic energy on the
perfectly conducting channel. We propose and calculate a backscattering
estimative in order to establish the connection between the perfectly
conducting channel (with ) and the amount of intervalley scattering.Comment: 7 pages, 9 figures. To be published on Phys. Rev.
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