Partition-free theory of time-dependent current correlations in nanojunctions in response to an arbitrary time-dependent bias
File(s)
Published version
Author(s)
Ridley, M
MacKinnon, A
Kantorovich, L
Type
Journal Article
Abstract
Working within the nonequilibrium Green’s function formalism, a formula for the two-time current correlation
function is derived for the case of transport through a nanojunction in response to an arbitrary time-dependent
bias. The one-particle Hamiltonian and the wide-band limit approximation are assumed, enabling us to extract all
necessary Green’s functions and self-energies for the system, extending the analytic work presented previously
[Ridley
et al.
,
Phys. Rev. B
91
,
125433
(
2015
)]. We show that our expression for the two-time correlation
function generalizes the Büttiker theory of shot and thermal noise on the current through a nanojunction to the
time-dependent bias case including the transient regime following the switch-on. Transient terms in the correlation
function arise from an initial state that does not assume (as is usually done) that the system is initially uncoupled,
i.e., our approach is partition free. We show that when the bias loses its time dependence, the long-time limit of
the current correlation function depends on the time difference only, as in this case an ideal steady state is reached.
This enables derivation of known results for the single-frequency power spectrum and for the zero-frequency
limit of this power spectrum. In addition, we present a technique which facilitates fast calculations of the transient
quantum noise, valid for arbitrary temperature, time, and voltage scales. We apply this formalism to a molecular
wire system for both dc and ac biases, and find a signature of the traversal time for electrons crossing the wire in
the time-dependent cross-lead current correlations.
function is derived for the case of transport through a nanojunction in response to an arbitrary time-dependent
bias. The one-particle Hamiltonian and the wide-band limit approximation are assumed, enabling us to extract all
necessary Green’s functions and self-energies for the system, extending the analytic work presented previously
[Ridley
et al.
,
Phys. Rev. B
91
,
125433
(
2015
)]. We show that our expression for the two-time correlation
function generalizes the Büttiker theory of shot and thermal noise on the current through a nanojunction to the
time-dependent bias case including the transient regime following the switch-on. Transient terms in the correlation
function arise from an initial state that does not assume (as is usually done) that the system is initially uncoupled,
i.e., our approach is partition free. We show that when the bias loses its time dependence, the long-time limit of
the current correlation function depends on the time difference only, as in this case an ideal steady state is reached.
This enables derivation of known results for the single-frequency power spectrum and for the zero-frequency
limit of this power spectrum. In addition, we present a technique which facilitates fast calculations of the transient
quantum noise, valid for arbitrary temperature, time, and voltage scales. We apply this formalism to a molecular
wire system for both dc and ac biases, and find a signature of the traversal time for electrons crossing the wire in
the time-dependent cross-lead current correlations.
Date Issued
2017-04-24
Date Acceptance
2017-02-28
Citation
Physical Review. B, 2017, 95 (16)
ISSN
0163-1829
Publisher
American Physical Society
Journal / Book Title
Physical Review. B
Volume
95
Issue
16
Copyright Statement
© 2017 American Physical Society
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000400066400011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Physics, Condensed Matter
Physics
CARBON NANOTUBE TRANSISTOR
PUMPED SHOT-NOISE
MOLECULAR WIRES
SCATTERING-THEORY
MESOSCOPIC CONDUCTORS
ELECTRON CONDUCTION
THERMAL AGITATION
TUNNELING CURRENT
DIAGRAM TECHNIQUE
FANO RESONANCE
Publication Status
Published
Article Number
ARTN 165440