Electron Transport through Nano-aperture in Ferroelectric Thin Film of Metal/Insulator(Stack of Ferroelectric and Non-ferroelectric)/Metal Junction

The electron energy band profile through a nm-scale circular aperture in ferroelectric thin film of metal/insulator(stack of ferroelectric and non-ferroelectric)/metal junction was calculated by performing finite-element electrostatic modeling. It is found that the energy band profile through the circular aperture alters significantly near the boundary of aperture depending on the polarization direction of ferroelectric thin film. The energy band profile shows pinch-off when the interface bound charge at Ferroelectric/Non-ferroelectric interface is negative while it shows a valley-like shape when the interface bound charge is positive. The change of the energy band profile depending on ferroelectric polarization was confirmed to result in a drastic change of electron tunneling probability through the non-ferroelectric insulating film inside the circular aperture by using WKB method. It is believed that this switching of electron tunneling resistance through the circular aperture opens a way to develop non-volatile ferroelectric memory devices using non-destructive read-out