Small InAsN and InN clusters: electronic properties and nitrogen stability belt

Quantum Dots of Indium Nitrides

“…Two groups of small indium nitride QDs have been studied [25,64,70,71] using symmetry considerations and the first-principle quantum many body theoretical methods, including HF, CI, CASSCF and MCSCF approximations. The first group includes 8 fcc-derived pyramidal-like molecules built of 10 In atoms, 3 or 2 As atoms and 1 or 2 N atoms.…”

“…25. It reflects remaining or acquired symmetries of the molecules via the presence of degenerate MOs.…”

“…These findings agree very well with numerous experimental observations [16,17,[56][57][58][59][60][61] indicating that electron charge in larger nanostructures and bulk lattices of the group III-V nitrides is re-distributed to the surface from the bulk to allow such broken symmetry systems minimize their total energy. This charge re-distribution is facilitated by the development of a new type of chemical bonding between ligand and other atoms in small atomic clusters resulting in formation of both non-stoichiometric and some stoichiometric molecules [25,[62][63][64][65]. The octet rule of the standard valence theory is violated in the case of non-stoichiometric molecules, as many atomic orbits (AOs) of the participating atoms contribute to the development of highly hybridized and delocalized molecular orbits (MOs) of such molecules.…”

“…However, as discussed elsewhere in literature (see, for example, Ref. 25), the majority of DFT-based methods suffer from various deficiencies that impact self-consistency and predictive capacity of such metods. In particular, to alleviate for the presence of 6 self-interactions and the absence of a variational procedure [26] that would allow approximation of the exchange-correlation functional (ECF) in a controlled manner (and thus could enable calculations of system properties with systematically improving accuracy), numerous semi-phenomenological ECFs, adjustable parameters, pseudopotentials and fitting potentials, such as the Hubbard potential [27], are used to calculate electronic energy level structure (ELS) and thermodynamic properties comparable in value to those obtained experimentally.…”

Electronic and magneto‐optic properties of Co‐ and Ni‐doped small quantum dots of indium nitrides

“…In this study constrained and unconstrained total energy minimization procedures based on these methods (see Ref. [3,4] and references therein) were used to model nucleation of small InN and InAsN QDs doped with Co or Ni atoms in quantum confinement and free space (below called vacuum). The obtained data on the electron energy level structure (ELS), charge and spin density distributions (CDDs and SDDs, respectively) of the studied small non-stoichiometric QDs elucidate microscopic mechanisms of their stabilization and an exceptional role played by quantum confinement and substitution doping in breaking symmetries of In-N and In-As-N structures, that otherwise would have developed into tetrahedrally symmetric QDs.…”