Spin-polarized electron emitter: Mn-doped GaN nanotubes and their arrays

Abstract

The influences from the doping magnetic atom, Mn, on the geometry, electronic properties, and spin-polarization characteristics are demonstrated for open armchair gallium nitrogen (GaN) nanotubes and arrays by use of the first-principles calculations. The interaction between dangling bonds of Ga (Mn) and N atoms at the open-end promotes the self-close of the tube mouth and formation of a more stable open semicone top. Primarily owing to hybridization of Mn $3d$ and N $2p$ orbitals, one Mn atom introduces several impurity energy levels into the original energy gap, and the calculated magnetic moment is $4{\ensuremath{\mu}}_{B}.$ The electron spin polarizations in the field emission are theoretically evaluated. We suggest that armchair open GaN nanotube arrays doped with a finite number of magnetic atoms may have application potential as the electron source of spintronic devices in the future.