Timedependent partitionfree 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 timedependent current response of a resonant tunneling system. We use a partitionfree 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 partitionfree approach has many appealing features being much closer to what is experimentally done. In particular, besides the steadystate responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steadystate 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 timedependent current response of a resonant tunneling system. We use a partitionfree 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 partitionfree approach has many appealing features being much closer to what is experimentally done. In particular, besides the steadystate responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steadystate 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 timedependent disturbances. We also show that the steadystate current is independent of the history of the external perturbation (memoryloss theorem). In the socalled wideband limit an analytic result for the timedependent current is obtained. In the interacting case we work out the lesser Green function in terms of the selfenergy and we recover a wellknown result in the longtime limit. In order to overcome the complications arising from a selfenergy which is nonlocal in time we propose an exact nonequilibrium Greenfunction approach based on timedependent densityfunctional theory. The equations are no more difficult than an ordinary meanfield treatment. We show how the scatteringstate scheme by Lang follows from our formulation. An exact formula for the steadystate current of an arbitrary interacting resonant tunneling system is obtained. As an example the timedependent current response is calculated in the randomphase approximation. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/905599
 author
 Stefanucci, Gianluca ^{LU} and Almbladh, CarlOlof ^{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
 10980121
 DOI
 10.1103/PhysRevB.69.195318
 language
 English
 LU publication?
 yes
 id
 0b3d918b1e5049c48bed950b3c9de086 (old id 905599)
 date added to LUP
 20080118 12:41:06
 date last changed
 20170924 04:25:18
@article{0b3d918b1e5049c48bed950b3c9de086, abstract = {An extended Keldysh formalism, well suited to properly take into account the initial correlations, is used in order to deal with the timedependent current response of a resonant tunneling system. We use a partitionfree 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 partitionfree approach has many appealing features being much closer to what is experimentally done. In particular, besides the steadystate responses one can also calculate physical dynamical responses. In the noninteracting case we clarify under what circumstances a steadystate 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 timedependent disturbances. We also show that the steadystate current is independent of the history of the external perturbation (memoryloss theorem). In the socalled wideband limit an analytic result for the timedependent current is obtained. In the interacting case we work out the lesser Green function in terms of the selfenergy and we recover a wellknown result in the longtime limit. In order to overcome the complications arising from a selfenergy which is nonlocal in time we propose an exact nonequilibrium Greenfunction approach based on timedependent densityfunctional theory. The equations are no more difficult than an ordinary meanfield treatment. We show how the scatteringstate scheme by Lang follows from our formulation. An exact formula for the steadystate current of an arbitrary interacting resonant tunneling system is obtained. As an example the timedependent current response is calculated in the randomphase approximation.}, author = {Stefanucci, Gianluca and Almbladh, CarlOlof}, issn = {10980121}, language = {eng}, number = {19}, publisher = {American Physical Society}, series = {Physical Review B (Condensed Matter and Materials Physics)}, title = {Timedependent partitionfree approach in resonant tunneling systems}, url = {http://dx.doi.org/10.1103/PhysRevB.69.195318}, volume = {69}, year = {2004}, }