Abstract
The rate-equation approach is used to describe sequential tunneling through a molecular junction in the Coulomb blockade regime. Such device is composed of molecular quantum dot (with discrete energy levels) coupled with two metallic electrodes via potential barriers. Based on this model, we calculate nonlinear transport characteristics (conductance-voltage and current-voltage dependences) and compare them with the results obtained within a self-consistent field approach. It is shown that the shape of transport characteristics is determined by the combined effect of the electronic structure of molecular quantum dots and by the Coulomb blockade. In particular, the following phenomena are discussed in detail: the suppression of the current at higher voltages, the charging-induced rectification effect, the charging-generated changes of conductance gap and the temperature-induced as well as broadening-generated smoothing of current steps.
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C. Joachim, J.K. Gimzewski and A. Aviram: “Electronics using hybrid-molecular and mono-molecular devices”, Nature (London), Vol. 408, (2000), pp. 541–548.
A. Nitzan and M.A. Ratner: “Electron transport in molecular wire junctions”, Science, (2003), Vol. 300, pp. 1384–1389.
J.R. Heath and M.A. Ratner: “Molecular electronics”, Phys. Today, Vol. 56, (2003), pp. 43–49.
A.W. Ghosh, P.S. Damle, S. Datta and A. Nitzan: “Molecular electronics: theory and device prospects”, MRS Bull., Vol. 29, (2004), pp. 391–395.
C. Zhou, M.R. Deshpande, M.A. Reed, L. Jones II and J.M. Tour: “Nanoscale metal/self-assembled monolayer/metal heterostructures”, Appl. Phys. Lett., Vol. 71, (1997), pp. 611–613.
M.A. Reed, C. Zhou, M.R. Deshpande, C.J. Muller, T.P. Burgin, L. Jones II and J.M. Tour: “The electrical measurement of molecular junctions”, Ann. N.Y. Acad. Sci., Vol. 852, (1998), pp. 133–144.
C. Kergueris, J.-P. Bourgoin, S. Palacin, D. Esteve, C. Urbina, M. Magoga and C. Joachim: “Electron transport through a metal/molecule/metal junction”, Phys. Rev. B, Vol. 59, (1999), pp. 12505–12513.
R.M. Metzger: “Electrical rectification by a molecule: the advent of unimolecular electronic devices”, Acc. Chem. Res., Vol. 32, (1999), pp. 950–957.
M.A. Reed: “Molecular-scale electronics”, Proc. IEEE, Vol. 87, (1999), pp. 652–658.
M. Burghard, C. Mueller-Schwanneke, G. Philipp and S. Roth: “Coulomb blockade phenomena in ultrathin Langmuir-Blodgett sandwich junctions”, J. Phys.: Condens. Matter, Vol. 11, (1999), pp. 2993–3002.
J. Park, A.N. Pasupathy, J.I. Goldsmith, C. Chang, Y. Yaish, J.R. Petta, M. Rinkoski, J.P. Sethna, H.D. Abruna, P.L. McEuen and D.C. Ralph: “Coulomb blockade and the Kondo effect in single-atom transistors”, Nature (London), Vol. 417, (2002), pp. 722–725.
K. Walczak: “Charging effects in biased molecular devices”, Physica E, Vol. 25, (2005), pp. 530–534.
M.M. Deshmukh, E. Bonet, A.N. Pasupathy and D.C. Ralph: “Equilibrium and nonequilibrium electron tunneling via discrete quantum states”, Phys. Rev. B, Vol. 65, (2002), pp. 073301.
C.W.J. Beenakker: “Theory of Coulomb blockade oscillations in the conductance of a quantum dot”, Phys. Rev. B, Vol. 44, (1991), pp. 1646–1656.
D.V. Averin, A.N. Korotkov and K.K. Likharev: “Theory of single-electron charging of quantum wells and dots”, Phys. Rev. B, Vol. 44, (1991), pp. 6199–6211.
J. von Delft and D.C. Ralph: “Spectroscopy of discrete energy levels in ultrasmall metallic grains”, Phys. Rep., Vol. 345, (2001), pp. 61–173.
E. Bonet, M.M. Deshmukh and D.C. Ralph: “Solving rate equations for electron tunneling via discrete quantum states”, Phys. Rev. B, Vol. 65, (2002), pp. 045317.
S. Datta: “Electrical resistance: an atomistic view”, Nanotechnology, Vol. 15, (2004), pp. S433–S451; Appendix A.
G. Roth and H. Fischer: “On the way to heptahexaenylidene complexes: trapping of an intermediate with the novel M=C=C=C=C=C=C=CR2 moiety”, Organometallics, Vol. 15, (1996), pp. 5766–5768.
N.D. Lang and Ph. Avouris: “Carbon-atom wires: charge-transfer doping, voltage drop, and the effect of distortions”, Phys. Rev. Lett., Vol. 84, (2000), pp. 358–361.
M. Di Ventra, S.T. Pantelides and N.D. Lang: “First-principles calculations of transport properties of a molecular device”, Phys. Rev. Lett., Vol. 84, (2000), pp. 979–982.
A.S. Alexandrov, A.M. Bratkovsky and R.S. Williams: “Bistable tunneling current through a molecular quantum dot”, Phys. Rev. B, Vol. 67, (2003), pp. 075301.
J.A. Wilson: “Developments in the negative U-modelling of the cuprate HTSC systems”, J. Phys.: Condens. Matter, Vol. 13, (2001), pp. R945–R977.
K. Walczak: “Nonlinear transport through a finite Hubbard chain connected to the electrodes”, Physica B, Vol. 365, (2005), pp. 193–200.
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Walczak, K. Coulomb blockade in molecular quantum dots. centr.eur.j.phys. 4, 8–19 (2006). https://doi.org/10.1007/s11534-005-0002-x
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DOI: https://doi.org/10.1007/s11534-005-0002-x