First-principles study on the electronic and magnetic properties of InN nanosheets doped with 2p elements

The electronic structure of InN nanosheets doped by light elements (Be, B, C, and O) is studied based on spin-polarized density functional theory within the generalized gradient approximation. The results show that the Be and C dopants in InN nanosheets induce spin polarized states in the band gap, or near the valence band, which generates local magnetic moments of 1.0 µB with one dopant atom. Due to the exchange spin-splitting, the three 2p electrons of Be atom are all in px and py orbitals (↑↑↓). So Be will coordinate with host atoms by σ coordination bond. The long-range ferromagnetic order above room temperature is attributed to p-p coupling. For C atom, the configuration of the five 2p electrons is (↑↑↑↓↓), and the unpaired electron is in pz(↑) orbital. So the π bond will be formed between C atom and other atoms. Due the weak π bond cannot support long-range coupling, no stable magnetism is sustained if two C dopants are separated by longer than 3.58 Å.