Investigation of Conductance and Capacitance of Mesoscopic and Molecular Scale Systems

Abstract

Afam Uzorka, Ademola Olatide Olaniyan and Mustaqeem Khan

In addition to a fundamental scientific interest, there has been a significant technological need to build and understand small-scale devices in order to maintain the current rate of progress in increasing computer performance. In this paper, we have discussed the modifications that must be made to the concepts of conductance and capacitance, if they are to be applicable to mesoscopic and molecular scale conductors. We have also reviewed the linear response capacitance theory of Bu �?ttiker, which can be used to determine the capacitance of a mesoscopic capacitor in a realistic geometry. In order to study capacitance and current at finite bias accurately in a molecular system, we must go beyond the linear response theory. The computational difficulties of determining the charge distribution in non-equilibrium can be resolved by the use of Green’s functions which we have reviewed. The system Hamiltonian can in turn be determined accurately by the methods of Density Functional Theory, which we have also outlined.

PDF