Si-Al2O3 interface

[akansha]

Sir,
how can we calculate the interface charge and fixed charge density at the si-al2o3 interface.

[Umberto Martinez]

You can analyze the electron density by using several analysis tools present in the Script Generator:
ElectronDensity
ElectronDifferenceDensity

these are 3D grids that you can plot and analyze from the LabFloor with the (3D) Viewer, the 1D projector (to plot the charge density across the interface and across yout device in general) or the Grid operation tools.

You can also calculate Mulliken population and compare your atoms at the interface with the bulk for example.
http://www.quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.mullikenpopulation.html

I am not familiar with fixed charge density but you should be able to get this quantity by using the tools mentioned above.