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Time-dependent partition-free approach in resonant tunneling systems

Stefanucci, Gianluca LU and Almbladh, Carl-Olof LU (2004) In Physical Review B (Condensed Matter and Materials Physics) 69(19).
Abstract
An extended Keldysh formalism, well suited to properly take into account the initial correlations, is used in order to deal with the time-dependent current response of a resonant tunneling system. We use a partition-free approach by Cini in which the whole system is in equilibrium before an external bias is switched on. No fictitious partitions are used. Despite a more involved formulation, this partition-free approach has many appealing features being much closer to what is experimentally done. In particular, besides the steady-state responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steady-state current develops and compare our result with the one obtained in... (More)
An extended Keldysh formalism, well suited to properly take into account the initial correlations, is used in order to deal with the time-dependent current response of a resonant tunneling system. We use a partition-free approach by Cini in which the whole system is in equilibrium before an external bias is switched on. No fictitious partitions are used. Despite a more involved formulation, this partition-free approach has many appealing features being much closer to what is experimentally done. In particular, besides the steady-state responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steady-state current develops and compare our result with the one obtained in the partitioned scheme. We prove a theorem of asymptotic equivalence between the two schemes for arbitrary time-dependent disturbances. We also show that the steady-state current is independent of the history of the external perturbation (memory-loss theorem). In the so-called wide-band limit an analytic result for the time-dependent current is obtained. In the interacting case we work out the lesser Green function in terms of the self-energy and we recover a well-known result in the long-time limit. In order to overcome the complications arising from a self-energy which is nonlocal in time we propose an exact nonequilibrium Green-function approach based on time-dependent density-functional theory. The equations are no more difficult than an ordinary mean-field treatment. We show how the scattering-state scheme by Lang follows from our formulation. An exact formula for the steady-state current of an arbitrary interacting resonant tunneling system is obtained. As an example the time-dependent current response is calculated in the random-phase approximation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
69
issue
19
publisher
American Physical Society
external identifiers
  • wos:000221961700064
  • scopus:37649026984
ISSN
1098-0121
DOI
10.1103/PhysRevB.69.195318
language
English
LU publication?
yes
id
0b3d918b-1e50-49c4-8bed-950b3c9de086 (old id 905599)
date added to LUP
2008-01-18 12:41:06
date last changed
2017-09-24 04:25:18
@article{0b3d918b-1e50-49c4-8bed-950b3c9de086,
  abstract     = {An extended Keldysh formalism, well suited to properly take into account the initial correlations, is used in order to deal with the time-dependent current response of a resonant tunneling system. We use a partition-free approach by Cini in which the whole system is in equilibrium before an external bias is switched on. No fictitious partitions are used. Despite a more involved formulation, this partition-free approach has many appealing features being much closer to what is experimentally done. In particular, besides the steady-state responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steady-state current develops and compare our result with the one obtained in the partitioned scheme. We prove a theorem of asymptotic equivalence between the two schemes for arbitrary time-dependent disturbances. We also show that the steady-state current is independent of the history of the external perturbation (memory-loss theorem). In the so-called wide-band limit an analytic result for the time-dependent current is obtained. In the interacting case we work out the lesser Green function in terms of the self-energy and we recover a well-known result in the long-time limit. In order to overcome the complications arising from a self-energy which is nonlocal in time we propose an exact nonequilibrium Green-function approach based on time-dependent density-functional theory. The equations are no more difficult than an ordinary mean-field treatment. We show how the scattering-state scheme by Lang follows from our formulation. An exact formula for the steady-state current of an arbitrary interacting resonant tunneling system is obtained. As an example the time-dependent current response is calculated in the random-phase approximation.},
  author       = {Stefanucci, Gianluca and Almbladh, Carl-Olof},
  issn         = {1098-0121},
  language     = {eng},
  number       = {19},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Time-dependent partition-free approach in resonant tunneling systems},
  url          = {http://dx.doi.org/10.1103/PhysRevB.69.195318},
  volume       = {69},
  year         = {2004},
}