17.11.20 - IRTG Seminar: Uri Peskin "Towards mechanically stable nano-scale electronic devices far from equilibrium"

 

Molecular junctions are electronic devices of a nanometer size, in which charge current flows through a single molecule linking two Fermion reservoirs under electric bias. The electronic structure and response of molecules give rise to appealing non-linear effects, with promising applications for information processing. Yet, excessive charging and discharging of the molecule during transport, especially far from equilibrium, transfer energy into molecular and contact vibrations, which induces heating, conformation changes or bond rupture, thus challenging the mechanical stability of these devices. In the talk we shall mention several mechanisms for transport induced mechanical instability in molecular junctions, and we shall focus on the phenomenon of vibrational heating during resonant charge transport. Our theoretical analysis suggests several new strategies for overcoming the excessive vibrational heating, including counter-intuitive effects, such as high-voltage assisted mechanical stabilization, cooling the molecule by heating the reservoirs, and plasmon-assisted cooling of molecular degrees of freedom. These results are explained using an analytical model and numerical simulations. Our work provides a new perspective on the energy content of nano-scale conductors far from equilibrium as well as some practical suggestions with respect to experimental control of the mechanical stability of nano-electronic devices.

 

 

 

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