Time-dependent quantum transport: A practical scheme using density functional theory

Kurth, Stefan; Stefanucci, Gianluca; Almbladh, Carl-Olof; Rubio, Ángel; Gross, E. K. U.

doi:10.1103/physrevb.72.035308

Cited by 314 publications

(454 citation statements)

References 63 publications

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“…The time-dependent version of density functional theory has also been used as framework for quantum transport. [23][24][25] This scheme is particularly useful for simulating transients and high frequency ac responses. Within the NEGF formalism, the many-body GW approxi-mation has been used to address correlated transport both under equilibrium 26 and nonequilibrium 27 conditions.…”

Section: Introductionmentioning

confidence: 99%

ConservingGWscheme for nonequilibrium quantum transport in molecular contacts

2008

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We give a detailed presentation of our recent scheme to include correlation effects in molecular transport calculations using the nonequilibrium Keldysh formalism. The scheme is general and can be used with any quasiparticle self-energy, but for practical reasons, we mainly specialize to the so-called GW self-energy, widely used to describe the quasiparticle band structures and spectroscopic properties of extended and lowdimensional systems. We restrict the GW self-energy to a finite, central region containing the molecule, and we describe the leads by density functional theory ͑DFT͒. A minimal basis of maximally localized Wannier functions is applied both in the central GW region and the leads. The importance of using a conserving, i.e., fully self-consistent, GW self-energy is demonstrated both analytically and numerically. We introduce an effective spin-dependent interaction which automatically reduces self-interaction errors to all orders in the interaction. The scheme is applied to the Anderson model in and out of equilibrium. In equilibrium at zero temperature, we find that GW describes the Kondo resonance fairly well for intermediate interaction strengths. Out of equilibrium, we demonstrate that the one-shot G 0 W 0 approximation can produce severe errors, in particular, at high bias. Finally, we consider a benzene molecule between featureless leads. It is found that the molecule's highest occupied molecular orbital-lowest unoccupied molecular orbital gap as calculated in GW is significantly reduced as the coupling to the leads is increased, reflecting the more efficient screening in the strongly coupled junction. For the I-V characteristics of the junction, we find that Hartree-Fock ͑HF͒ and G 0 W 0 ͓G HF ͔ yield results closer to GW than does DFT and G 0 W 0 ͓G DFT ͔. This is explained in terms of selfinteraction effects and lifetime reduction due to electron-electron interactions.

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Section: Introductionmentioning

confidence: 99%

ConservingGWscheme for nonequilibrium quantum transport in molecular contacts

2008

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“…23,25 Since the method only involves the propagation of single-particle wave functions, it provides a computationally efficient way to study time-dependent phenomena in quantum transport. 26 The real-time TDDFT approach to transport will be described in Sec. III A.…”

Section: Multistability In Time-dependent Density Functional Theorymentioning

confidence: 99%

“…[20][21][22][23][24][25][26][27][28][29][31][32][33][34] We first solve the steady-state equations of DFT and mean-field theory to determine the parameter range for bistability. Then we go beyond the current state-of-the-art and provide a TD description of the bistability phenomenon in adiabatic TDDFT [23][24][25][26][27][28][29] and TD mean-field theory. We show how to switch between different stable states by means of ultrafast gate voltages or external biases (driving fields).…”

Section: Introductionmentioning

confidence: 99%

Correlation effects in bistability at the nanoscale: Steady state and beyond

et al. 2012

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The possibility of finding multistability in the density and current of an interacting nanoscale junction coupled to semi-infinite leads is studied at various levels of approximation. The system is driven out of equilibrium by an external bias and the nonequilibrium properties are determined by real-time propagation using both time-dependent density functional theory (TDDFT) and many-body perturbation theory (MBPT). In TDDFT the exchange-correlation effects are described within a recently proposed adiabatic local density approximation (ALDA). In MBPT the electron-electron interaction is incorporated in a many-body self-energy which is then approximated at the Hartree-Fock (HF), second-Born, and GW level. Assuming the existence of a steady state and solving directly the steady-state equations we find multiple solutions in the HF approximation and within the ALDA. In these cases we investigate whether and how these solutions can be reached through time evolution and how to reversibly switch between them. We further show that for the same cases the inclusion of dynamical correlation effects suppresses bistability.

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“…2 They and their coworkers have further proposed a practical scheme in which the electronic wavefunction propagates in time domain subject to open boundaries. 3 The resulting numerical method has been tested on model systems. However, its applicability to realistic electronic devices remains unexploited.…”

Section: Introductionmentioning

confidence: 99%

“…[2][3][4][5][6][7][8][9][10] As a formally rigorous and numerically tractable approach, TDDFT promises real-time simulations on ultrafast electron transport through realistic electronic devices or structures. In early attempts, finite source-device-drain systems were treated by the conventional TDDFT for isolated systems.…”

Section: Introductionmentioning

confidence: 99%

Time-dependent density functional theory for quantum transport

2013

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Based on our earlier works [Phys. Rev. B 75, 195127 (2007) & J. Chem. Phys. 128, 234703 (2008], we propose a formally exact and numerically convenient approach to simulate time-dependent quantum transport from first-principles. The proposed approach combines time-dependent density functional theory with quantum dissipation theory, and results in a useful tool for studying transient dynamics of electronic systems. Within the proposed exact theoretical framework, we construct a number of practical schemes for simulating realistic systems such as nanoscopic electronic devices. Computational cost of each scheme is analyzed, with the expected level of accuracy discussed. As a demonstration, a simulation based on the adiabatic wide-band limit approximation scheme is carried out to characterize the transient current response of a carbon nanotube based electronic device under time-dependent external voltages.

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Time-dependent quantum transport: A practical scheme using density functional theory

Cited by 314 publications

References 63 publications

ConservingGWscheme for nonequilibrium quantum transport in molecular contacts

ConservingGWscheme for nonequilibrium quantum transport in molecular contacts

Correlation effects in bistability at the nanoscale: Steady state and beyond

Time-dependent density functional theory for quantum transport

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