2,298 research outputs found
Fully Overheated Single-Electron Transistor
We consider the fully overheated single-electron transistor, where the heat
balance is determined entirely by electron transfers. We find three distinct
transport regimes corresponding to cotunneling, single-electron tunneling, and
a competition between the two. We find an anomalous sensitivity to temperature
fluctuations at the crossover between the two latter regimes that manifests in
an exceptionally large Fano factor of current noise.Comment: 6 pages, 3 figures, includes Appendi
Coulomb Blockade due to Quantum Phase-Slips Illustrated with Devices
In order to illustrate the emergence of Coulomb blockade from coherent
quantum phase-slip processes in thin superconducting wires, we propose and
theoretically investigate two elementary setups, or "devices". The setups are
derived from Cooper-pair box and Cooper-pair transistor, so we refer to them as
QPS-box and QPS-transistor, respectively. We demonstrate that the devices
exhibit sensitivity to a charge induced by a gate electrode, this being the
main signature of Coulomb blockade. Experimental realization of these devices
will unambiguously prove the Coulomb blockade as an effect of coherence of
phase-slip processes. We analyze the emergence of discrete charging in the
limit strong phase-slips. We have found and investigated six distinct regimes
that are realized depending on the relation between three characteristic energy
scales: inductive and charging energy, and phase-slip amplitude. For
completeness, we include a brief discussion of dual Josephson-junction devices
Full Current Statistics in the Regime of Weak Coulomb Interaction
We evaluate the full statistics of the current via a Coulomb island that is
strongly coupled to the leads. This strong coupling weakens Coulomb
interaction. We show that in this case the effects of the interaction can be
incorporated into the renormalization of transmission eigenvalues of the
scatterers that connect the island and the leads. We evaluate the Coulomb
blockade gap in the current-voltage characteristics, the value of the gap being
exponentially suppressed as compared to the classical charging energy of the
island.Comment: 4 pages, 3 figure
Trapped modes in zigzag graphene nanoribbons
We study a scattering on an ultra-low potential in zigzag graphene
nanoribbon. Using mathematical framework based on the continuous Dirac model
and augumented scattering matrix, we derive a condition for the existence of a
trapped mode. We consider the threshold energies where the continuous spectrum
changes its multiplicity and show that the trapped modes may appear for
energies slightly less than a threshold and its multiplicity does not exceeds
one. We prove that trapped modes do not appear outside the threshold, provided
the potential is sufficiently small
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