Atk/vnl can be best utilized to get the different features like DOS, Band Structure, Transmission Spectrum and many more...for the material of your interest or, for the device structure you made. You have the options for choosing the material, setting its orientation, modifying structure of the device to a particular shape, as well as the selecting different values for the parameters like voltage, temp. etc. while simulating.
Now, you can utilize those basic information (which are relevant, and obtained from the different analyses), to form a code using any scripter (say, for example MATLAB); where actually you may use the different fitting values to characterize your device properly. So that, you end up with a set of results that actually you were looking for.
