|
Magnetism without magnetic elements, so-called "d0 magnetism", is of fundamental interest. In particular, nitrogen-dangling bonds of cation vacancies are responsible for spin polarization in nitride semiconductors [1]. However, randomness of point-defect distribution is not feasible to control magnetization. In this situation, ordered structures of spin sites are highly desirable for the control of magnetization. In this study, we demonstrate by means of first-principles calculations that nitride-boride interfaces could be a candidate for such ordered spin sites [2]. Partially occupied N p states at AlN-MgB2(0001) interfaces exhibits two-dimensional spin polarization. Hund's coupling of the two N p|| orbitals as well as high density of spin-unpolarized states at the Fermi energy contribute to itinerant ferromagnetism. Roles of metal-induced gap states [3] will also be discussed. [1] Y. Gohda and A. Oshiyama, Phys. Rev. B 78, 161201(R) (2008). [2] Y. Gohda and S. Tsuneyuki, Phys. Rev. Lett. 106, 047201 (2011). [3] Y. Gohda, S. Watanabe, and A. Gross, Phys. Rev. Lett. 101, 166801 (2008). |
|