Time-dependent partition-free approach in resonant tunneling systems
(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)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/905599
- author
- Stefanucci, Gianluca LU and Almbladh, Carl-Olof LU
- organization
- publishing date
- 2004
- 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
- 2016-04-01 16:16:24
- date last changed
- 2022-01-28 18:33:57
@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}},
doi = {{10.1103/PhysRevB.69.195318}},
volume = {{69}},
year = {{2004}},
}