Engineering:Electromigrated nanogaps

Electromigrated Nanogaps are gaps formed in metallic bridges formed by the process of electromigration.

Theory

A nanosized contact formed by electromigration acts like a waveguide for electrons. The nanocontact essentially acts like a one-dimensional wire with a conductance of $G=2e^2/h$. The current in a wire is the velocity of the electrons multiplied by the charge and number per unit length, $I=veN/L$ or $G=veN/LV$. This gives a conductance of $G=v{e}^{2}N/LE$. In nano scale bridges the conductance falls in discrete steps of multiples of the quantum conductance $G=2e^2/h$.

Uses

• Electromigrated Nanogaps have shown great promise as electrodes in use in molecular scale electronics.
• Researcher have used feedback controlled electromigration to investigate the magnetoresistance of a quantum spin valve.