A first-principles study on the effect of point defects on the magnetism of the AlN:Li/Na/K system

Abstract

When AIN semiconductors are grown by metal–organic chemical vapor deposition and vacuum-coating methods, interstitial H atoms are unintentionally incorporated into AlN and are often overlooked. To solve this problem, the present study adopted the first-principles hybrid functional HSE06 method under the framework of density functional theory to examine the impact of the point defects (VAl and Hi) on the magnetic properties of the AlN:Li/Na/K system. Results showed that all doped systems had single-ion spin-polarized N2− at different positions to generate magnetism, different from the source of magnetic coupling in conventional doped systems. Compared with the Al34MN36 (M = Li/Na) and Al34N36 systems, the magnetic moments of the Al34MHiN36 (M = Li/Na) and Al34HiN36 systems increased after incorporating the interstitial H. Moreover, the Al34MHiN36 (M = Li/Na) and Al34HiN36 systems unpaired itinerant electrons, and the magnetism was generated mostly by the unpaired itinerant electrons of N2− ions. The itinerant electrons exchanged electrons through Al vacancies to generate magnetism. Furthermore, the total magnetic moment of the Al34KHiN36 and Al35HiN36 systems were zero, and the use of interstitial H regulation as magnetic switches was very advantageous for these systems.