Coherence in charge and energy transfer in molecular junctions

We consider the effects of dephasing on field-induced coherent charge and energy transport in molecular junctions. Within generic models we show that dephasing controls the relative intensities of energy and charge fluxes, and that the dependence of the energy flux on the dephasing rate is nonmonotonic. We further demonstrate the possibility for laser-controlled charge-energy separation in multiterminal molecular junctions, a prerequisite for engineering low-heating stable nanoscale devices.

Figure 1

A sketch of the models for coherently controlled charge-energy (a) pump and (b) switch.

Figure 2

Molecular pump [Fig. 1a]. Shown are the charge [$I_3^c$, Eq. (9)—solid line, blue] and energy [$I_3^E$, Eq. (10)—dashed line, red] fluxes on the right interface as functions of dephasing rate ${\gamma }^{B_d}$ [Eq. (15)]. See text for parameters.

Figure 3

Molecular switch [Fig. 1b]. Shown are charge [$I_1^c$—solid line, blue; $I_2^c$—dotted line, dark blue; Eq. (9)], and energy [$I_1^E$—dashed line, red; $I_2^E$—dash-dotted line, magenta; Eq. (10)] fluxes as functions of (a) the driving amplitude ${\mu }_0{E}_0$ and (b) frequency ${\omega }_0$ [Eq. (2)]. See text for parameters.

Figure 4

Molecular dimer. Shown are (a) schemes for charge (top) and energy (bottom) transfer; (b) relevant many-body states of the molecule, charge $T^c\left(E\right)$ (left, blue) and energy $T^E\left(E\right)$ (right, red) transmission coefficients as functions of energy $E$; (c) the driving amplitude ${\mu }_0{E}_0$; and (d) frequency ${\omega }_0$. See text for details.