Heat currents in electronic junctions driven by telegraph noise

The energy and charge fluxes carried by electrons in a two-terminal junction subjected to a random telegraph noise, produced by a single electronic defect, are analyzed. The telegraph processes are imitated by the action of a stochastic electric field that acts on the electrons in the junction. Upon averaging over all random events of the telegraph process, it is found that this electric field supplies, on the average, energy to the electronic reservoirs, which is distributed unequally between them: the stronger is the coupling of the reservoir with the junction, the more energy it gains. Thus the noisy environment can lead to a temperature gradient across an unbiased junction.

Figure 1

Schematic picture of the model junction: a localized electronic level is coupled to two electronic reservoirs, held at chemical potentials ${\mu }_L$ and ${\mu }_R$, at temperatures $T_L$ and $T_R$, respectively. An electron residing on this level is subjected to a stochastic electric field. This is imitated by a stochastic time dependence of the level energy, ${\epsilon }_d\left(t\right)$. The coupling with the reservoirs causes the level $\epsilon$ to become a resonance, of width $\mathrm{\Gamma }={\mathrm{\Gamma }}_L+{\mathrm{\Gamma }}_R$, where ${\mathrm{\Gamma }}_L,{\mathrm{\Gamma }}_R$ are the partial widths.

Figure 2

The power absorbed by the junction (in units of the effective electric field squared, $\overline{{\mathcal{E}}^2})$, for identical electronic reservoirs (see text), $\overline{\xi }=0.5$ and $\gamma =1$. The different curves with increasing dashes are for $\epsilon -\mu =0.1$, 1, 5. (Energies are in units of $\mathrm{\Gamma }$.)