  The electrostatic behaviour of an 1,3-Cyclobutadiene (C$_{4}$H$_{4}$) based
Single Molecular Transistor (SMT) has been investigated using the first
principle calculation based on Density functional Theory and non-equilibrium
Green's function approach. While the molecule is placed on top of a dielectric
layer (backed by a metallic gate) and weakly coupled between the Source/Drain
electrodes, the charge stability diagram revealed the presence of individual
charge states in the Coulomb Blockade regime. This gets affected significantly
on addition of an another gate electrode placed on the top of the molecule.
This modified double-gated geometry allows additional control of the total
energy of the system that is sensitive to the individual charge states of the
molecule which can be used as a charge sensing technique operational at room
temperature.
