The effects of dangling bond on the electronic and magnetic properties of armchair AlN/SiC heterostructure nanoribbons

First-principles calculations are performed to investigate the electronic and magnetic properties of armchair AlN/SiC heterostructure nanoribbons (A(AlN)_x(SiC)_11-xNRs). A(AlN) _x(SiC)_11-xNRs (x = 0, 3, 5, 7, 9 and 11) with H terminated at both edges are all semiconductors with direct band gaps, and a tunable band gap can be obtained via controlling the composition ratio of AlN/SiC nanoribbons. The unpassivated edge Al, N, Si or C atom can cause magnetic moments, which may open a way to design magnetic nanodevices based on AlN/SiC heterostructure nanoribbons. In additional, these systems with dangling bond are changed to magnetic semiconductors with indirect band gaps, the band gap change from direct to indirect is important in the practical application as light emitting devices. The net charge mainly accumulates at the bared atom, and a small part of contribution of magnetic moments can be attributed to the neighboring atoms with larger electronegativity than the bared atom.