1 research outputs found
From Bloch Oscillations to a Steady-State Current in Strongly Biased Mesoscopic Devices
It has long been known that quantum particles in a periodic lattice exhibit
an oscillatory motion that is solely driven by a constant and uniform force
field. In a strongly biased mesoscopic device, this would appear as an ongoing
time-dependent current oscillation (a Bloch oscillation) but, even when
electrons can move coherently and without scattering, a steady-state regime of
charge transport (a Landauer current) have been seen to quickly emerge. Here,
we theoretically investigate the non-equilibrium current dynamics of a strongly
biased two-terminal mesoscopic device, in order to show that such a system can
exhibit Bloch oscillations as a transient regime that relaxes into a Landauer
steady-state from charge being drained into the leads. Analytical results from
the one-dimensional Wannier-Stark ladder problem are combined with numerical
quantum time-evolution of a tight-binding toy model with finite leads to
characterize the decay times of transient Bloch oscillations and establish the
conditions under which they can occur.Comment: Preliminary Version (13 pages + 12 Figures). Comments and Suggestions
are Welcome