Tuning of electron transport through a quantum wire: An exact study

We explore electron transport properties in a quantum wire attached to two metallic electrodes. A simple tight-binding model is used to describe the system and the coupling of the wire to the electrodes (source and drain) is treated through Newns-Anderson chemisorption theory. In our present model, the site energies of the wire are characterized by the relation $ε_i=W\cos(i λ^νπ)$ where $W$, $λ$, $ν$ are three positive numbers. For $ν=0$, the threshold bias voltage of electron conduction across the bridge can be controlled very nicely by tuning the strength of the potential $W$. On the other hand, for $ν\ne 0$, the wire becomes an aperiodic one and quite interestingly we see that, for some special values of $ν$, the system exhibits a {\em metal-insulator} transition which provides a significant feature in this particular study. Our numerical results may be useful for fabrication of efficient switching devices.

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