Approach to steady-state transport in nanoscale conductors

Nano Letters

Volumn 5, Issue 12, 2005, Pages 2569-2572

  Bushong, Neil ^a   Sai, Na ^a   Di Ventra, Massimiliano ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

DENSITY-FUNCTIONAL THEORY; NANOSCALE CONDUCTORS; QUASI-STEADY-STATE CURRENT; RESULTANT CONDUCTANCE;

ELASTICITY; ELECTRIC POTENTIAL; ELECTRODES; ELECTRONS; FERMI LEVEL; PROBABILITY DENSITY FUNCTION;

NANOSTRUCTURED MATERIALS;

NANOMATERIAL;

ARTICLE; CHEMICAL MODEL; CHEMICAL STRUCTURE; CHEMISTRY; COMPUTER SIMULATION; ELECTRIC CONDUCTIVITY; ELECTROCHEMISTRY; ELECTROMAGNETIC FIELD; ELECTRON; ELECTRON TRANSPORT; METHODOLOGY; NANOTECHNOLOGY; SEMICONDUCTOR;

COMPUTER SIMULATION; ELECTRIC CONDUCTIVITY; ELECTROCHEMISTRY; ELECTROMAGNETIC FIELDS; ELECTRON TRANSPORT; ELECTRONS; MODELS, CHEMICAL; MODELS, MOLECULAR; NANOSTRUCTURES; NANOTECHNOLOGY; SEMICONDUCTORS;

EID: 30644470693     PISSN: 15306984     EISSN: None     Source Type: Journal    
DOI: 10.1021/nl0520157     Document Type: Article

References (25)

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12. A. P. Horsfield and T. N. Todorov have communicated to us that they also find steady currents in the absence of inelastic effects, but they have never reported their results in any publication (private communication).
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17. The matrix element r = -11 eV is chosen so that the time scales of the TB calculation are comparable to those in the TDDFT calculation for the same number of atoms in the system.
18. This is just one of the many (essentially infinite) initial conditions one can choose to initiate current flow. However, note that some initial conditions may not lead to a quasi-steady state. The question of the dependence of steady states on initial conditions has been addressed in refs 5 and 20 and will be analyzed in more detail in a future publication.
19. Note that, in the 3D case, a quasi-steady state can be established only if the typical energy spacing of lateral modes of the electrodes is much smaller than the corresponding one in the junction.
20. Kurth S.; Stefanucci, G.; Almbladh, C.-O.; Rubio, A.; Gross, E. K. U. Phys. Rev. B 2005, 72, 035308.
21. The calculations reported here have been done using the socorro package (http://dft.sandia.gov/Socorro/mainpage.html), adapted by Ryan Hatcher to perform time-dependent calculations.
22. As in the TB case, we construct the initial state of the system such that the left-hand side of the gold chain has a deficiency of charge and the right-hand side has a surplus; we use a steplike potential to create this imbalance at t = 0. The current is similarly determined by differentiating in time the charge accumulating on the left side.
23. Kohn, W.; Sham, L. J. Phys. Rev. 1965, 140, A1133.
24. Note that in the static formulation of transport there is a conceptual (albeit numerically small, see, e.g.: Di Ventra, M.; Lang, N. D. Phys. Rev. B 2002, 65, 045402) distinction between the chemical potential difference and the electrostatic potential drop, the conductance being usually defined in terms of the former.
25. We have recently shown that there exist dynamical corrections to the electron conductance obtained using ALDA which exists even in the limit of zero frequency (Sai, N.; Zwolak, M.; Vignale, G.; Di Ventra, M. Phys. Rev. Lett. 2005, 94, 186810). These corrections depend on the gradient of the electron density and are therefore negligible for a gold quantum point contact. Combined with the theorem in ref 5 on the exact value of the TDDFT total current in a closed and finite system, this result shows that the TDDFT-ALDA current of a gold junction at steady state is very close to the exact many-body value.