Electron energy-loss spectra of non-polar GaN surfaces

We calculate the electron energy-loss spectra (EELS) of the non-polar GaN(< 10(1)over bar 0>) and (110) surfaces The calculations are done using a real istic microscopic model within the tight-binding approach. Results are pres ented in terms of differential EELS that allows a direct comparison with ex periments. The discussion of the spectra is done in terms of the difference between the surface atomic reconstruction of the wurtzite and cubic surfac es, as well as in terms of their respective surface electronic states.