Electric Field-induced switching among multiple conductance pathways in single-molecule junctions

Here, we report the switching among multiple conductance pathways achieved by sliding the scanning tunneling microscope tip among different binding sites under different electric fields. With the electric field increase,...

Overshoot dependence on the cross-shock potential

Coherent downstream oscillations of the magnetic field in shocks are produced due to the coherent ion gyration and quasi-periodic variations of the ion pressure. The amplitude and the positions of the pressure maxima and minima depend on the cross-shock potential and upstream ion temperature. Two critical potentials are defined: the critical gyration potential (CGP) which separates the cases of increase or decrease of the normal velocity of the distribution center, and the critical reflection potential (CRP) above which ion reflection becomes significant. In weak very low β shocks CRP exceeds CGP. For potentials below CGP the first downstream maximum of the magnetic field is shifted farther downstream and is larger than the second one. For higher potentials the first maximum occurs just behind the ramp and is lower than the second one. With the increase of the upstream temperature CGP exceeds the CRP. For potentials below CRP the effects of ion reflection are negligible and the shock profile is similar to that of very low β shocks. If the potential exceeds CRP ion reflection is significant, the magnetic field increase toward the overshoot becomes steeper, and the largest peak occurs at the downstream edge of the ramp.