Recent experimental investigations show that the measurement unimolecular transport is possible. Still, signatures of truly moleculemediated quantum transport have to be selectively identified in experiments and their theoretical mechanisms need to be understood. Such signatures can be obtained by separating an aromatic molecule into two electronically different parts. This can be attained by the substitution of certain H-atoms asymmetrically on one side of phenylene ethynylene based molecules by atoms with larger electronegativity (e.g. F). Then, the d-conjugation can be broken by means of steric repulsion groups like NO2 and/or CH3. Depending on the position of these groups on the molecule, it is possible to further engineer electrical dipoles able to incrementally break the l-conjugation in response to an external electric field. We have thus investigated nonlinear quantum transport through phenylene ethynylene based molecules as a function of a gatable intramolecular coupling to understand the role of chemical substitution the observable nonequilibrium electrical current. Contacts to the recent experiments by Elbing et al. [1] are also provided.
[1] M. Elbing et al., Proc. Natl. Acad. Sci. USA 102, 8815 (2005).
Recent experimental investigations show that the measurement unimolecular transport is possible. Still, signatures of truly moleculemediated quantum transport have to be selectively identified in experiments and their theoretical mechanisms need to be understood. Such signatures can be obtained by separating an aromatic molecule into two electronically different parts. This can be attained by the substitution of certain H-atoms asymmetrically on one side of phenylene ethynylene based molecules by atoms with larger electronegativity (e.g. F). Then, the d-conjugation can be broken by means of steric repulsion groups like NO2 and/or CH3. Depending on the position of these groups on the molecule, it is possible to further engineer electrical dipoles able to incrementally break the l-conjugation in response to an external electric field. We have thus investigated nonlinear quantum transport through phenylene ethynylene based molecules as a function of a gatable intramolecular coupling to understand the role of chemical substitution the observable nonequilibrium electrical current. Contacts to the recent experiments by Elbing et al. [1] are also provided.
[1] M. Elbing et al., Proc. Natl. Acad. Sci. USA 102, 8815 (2005).
