Molecular conduction: Do time-dependent simulations tell you more than the Landauer approach?

Sánchez, Cristián G.; Stamenova, Maria; Sanvito, Stefano; Bowler, David R.; Horsfield, Andrew P.; Todorov, Tchavdar N.

doi:10.1063/1.2202329

Cited by 82 publications

(105 citation statements)

References 30 publications

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“…For the 1D tight-binding leads the retarded embedding selfenergy has the structure (14) and therefore the self-consistency condition (10) becomes…”

Section: B Adiabatic Approximation: Steady-state Condition For the Dmentioning

confidence: 99%

“…At the Hartree level, bistability was reported for a double quantum dot structure. 13,14 In the context of time-dependent (TD) DFT, the inclusion of memory effects beyond the adiabatic approximation is not straightforward and the development of accurate functionals to be used in numerical calculations is still under way. A promising and timely, even though computationally demanding, alternative is the solution of the Kadanoff-Baym (KB) equations [15][16][17][18][19][20][21] using self-energies from many-body perturbation theory (MBPT).…”

Section: Introductionmentioning

confidence: 99%

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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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“…For the 1D tight-binding leads the retarded embedding selfenergy has the structure (14) and therefore the self-consistency condition (10) becomes…”

Section: B Adiabatic Approximation: Steady-state Condition For the Dmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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“…Thus, the external perturbation is a local potential and the partitionfree approach can be combined with Time-Dependent Density Functional Theory 13,14,15,16 (TDDFT) to calculate total currents and densities in interacting systems. 7,8 The use of TDDFT in quantum transport is gaining ground 7,8,10,17,18,19,20,21,22,23,24,25,26,27,28,29 and several properties of the time-dependent exchangecorrelation potential and kernel have recently been discussed. 30,31,32,33,34 In a previous work 6 we have shown how a steady current develops under the influence of a constant bias.…”

Section: 910mentioning

confidence: 99%

Bound states inab initioapproaches to quantum transport: A time-dependent formulation

Stefanucci

2007

Phys. Rev. B

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In this work we study the role of bound electrons in quantum transport. The partition-free approach by Cini is combined with time-dependent density functional theory (TDDFT) to calculate total currents and densities in interacting systems. We show that the biased electrode-deviceelectrode system with bound states does not evolve towards a steady regime. The density oscillates with history-dependent amplitudes and, as a consequence, the effective potential of TDDFT oscillates too. Such time dependence might open new conductive channels, an effect which is not accounted for in any steady-state approach and might deserve further investigations.

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“…18 This term, which depends on a driving rate parameter (Γ), allows to maintain the charge imbalance after the external potential is turned off, by restoring the elements of the density matrix associated with the leads back to the polarized state. With this strategy the backscattering inherent to microcanonical dynamics is avoided and the system can reach a steady state.…”

Section: Introductionmentioning

confidence: 99%

Electron transport in real time from first-principles

Morzan

Ramirez

Lebrero

et al. 2017

The Journal of Chemical Physics

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While the vast majority of calculations reported on molecular conductance have been based on the static non-equilibrium Green's function formalism combined with density functional theory (DFT), in recent years a few time-dependent approaches to transport have started to emerge. Among these, the driven Liouville-von Neumann equation [C. G. Sánchez et al., J. Chem. Phys. 124, 214708 (2006)] is a simple and appealing route relying on a tunable rate parameter, which has been explored in the context of semi-empirical methods. In the present study, we adapt this formulation to a density functional theory framework and analyze its performance. In particular, it is implemented in an efficient allelectron DFT code with Gaussian basis functions, suitable for quantum-dynamics simulations of large molecular systems. At variance with the case of the tight-binding calculations reported in the literature, we find that now the initial perturbation to drive the system out of equilibrium plays a fundamental role in the stability of the electron dynamics. The equation of motion used in previous tight-binding implementations with massive electrodes has to be modified to produce a stable and unidirectional current during time propagation in time-dependent DFT simulations using much smaller leads. Moreover, we propose a procedure to get rid of the dependence of the current-voltage curves on the rate parameter. This method is employed to obtain the current-voltage characteristic of saturated and unsaturated hydrocarbons of different lengths, with very promising prospects. Published by AIP Publishing. [http://dx

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Molecular conduction: Do time-dependent simulations tell you more than the Landauer approach?

Cited by 82 publications

References 30 publications

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

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

Bound states inab initioapproaches to quantum transport: A time-dependent formulation

Electron transport in real time from first-principles

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