Spin Electronic States of GaN Probes : Magnetism of Nanostructures  [in Japanese]

We conducted a preliminary study of the spin electronic states of GaN nanocrystal probes to show the mechanism of spin polarization in nanoscale materials. We constructed four cluster models for GaN tips in the zincblende structure and calculated the electruonics states, using the ab initio molecular orbital theory. The spin states varied as the proportion of polarized valence electrons ranged from 0% to 70%. It was found that at the pyramidal heads of the probes, the electron spins were polarized in the lowest energy states. Approximately 11% to 34% of electrons in the valence hand were spin-polarized in the proximity of the head, depending on the kind of atom at the apex and the crystallographic axis of the probe. These results indicate higher spin polarization than we suggested in our previous study [J. Mag. Soc. Jpn. 23, No. 1-2]. It seems that spin polarization grows as the difference of the electronegativities of the elements in a compound increases, and that it can be enhanced by a highly symmetric probe nanostucture.