ترغب بنشر مسار تعليمي؟ اضغط هنا

Controlled electron transport through single molecules

148   0   0.0 ( 0 )
 نشر من قبل Iain Grace
 تاريخ النشر 2006
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Using a first principles approach, we study the electron transport properties of a new class of molecular wires containing fluorenone units, whose features open up new possibilities for controlling transport through a single molecule. We show that the presence of side groups attached to these units leads to Fano resonances close to the Fermi energy. As a consequence electron transport through the molecule can be controlled either by chemically modifying the side group, or by changing the conformation of the side group. This sensitivity, opens up new possibilities for novel single-molecule sensors. We also show that transport can be controlled by tilting a molecule with respect to the electrode surfaces. Our results compare favorably with recent experiments.

قيم البحث

اقرأ أيضاً

Scanning tunneling spectra on single C60 molecules that are sufficiently decoupled from the substrate exhibit a characteristic fine structure, which is explained as due to the dynamic Jahn-Teller effect. Using electron-phonon couplings extracted from density functional theory we calculate the tunneling spectrum through the C60- anionic state and find excellent agreement with measured data.
We provide a simple set of rules for predicting interference effects in off-resonant transport through single-molecule junctions. These effects fall in two classes, showing respectively an odd or an even number of nodes in the linear conductance with in a given molecular charge state, and we demonstrate how to decide the interference class directly from the contacting geometry. For neutral alternant hydrocarbons, we employ the Coulson-Rushbrooke-McLachlan pairing theorem to show that the interference class is decided simply by tunneling on and off the molecule from same, or different sublattices. More generally, we investigate a range of smaller molecules by means of exact diag- onalization combined with a perturbative treatment of the molecule-lead tunnel coupling. While these results generally agree well with GW calculations, they are shown to be at odds with simpler mean-field treatments. For molecules with spin-degenerate ground states, we show that for most junctions, interference causes no transmission nodes, but argue that it may lead to a non-standard gate-dependence of the zero-bias Kondo resonance.
The vibrational modes of Jahn-Teller molecules are affected by a Berry phase that is associated with a conical intersection of the adiabatic potentials. We investigate theoretically how this Berry phase affects transport through a single $E otimes e$ Jahn-Teller molecule when the tunneling electrons continually switch the molecule between a symmetric and a Jahn-Teller distorted charge state. We find that the Berry phase in conjunction with a spectral trapping mechanism leads to a current blockade even in regions outside the Coulomb blockade. The blockade is strongly asymmetric in the gate voltage and induces pronounced negative differential conductance.
The single-molecule conductance of a 3-ring, conjugated azomethine was studied using the mechanically controlled breakjunction technique. Charge transport properties are found to be comparable to vinyl-based analogues; findings are supported with den sity functional calculations. The simple preparation and good transport properties make azomethine-based molecules an attractive class for use in polymer and single-molecule organic electronics.
155 - Jens Koch , M.E. Raikh , 2005
We study analytically the full counting statistics of charge transport through single molecules, strongly coupled to a weakly damped vibrational mode. The specifics of transport in this regime - a hierarchical sequence of avalanches of transferred ch arges, interrupted by quiet periods - make the counting statistics strongly non-Gaussian. We support our findings for the counting statistics as well as for the frequency-dependent noise power by numerical simulations, finding excellent agreement.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا