Produção Nacional
Monte Carlo simulations applied to Al x Ga y In 1 − x − y X quaternary …
2005; American Physical Society; Volume: 71; Issue: 20 Linguagem: Inglês
10.1103/physrevb.71.205204
ISSN1550-235X
AutoresMiguel A. L. Marques, L. G. Ferreira, L. K. Teles, L. M. R. Scolfaro,
Tópico(s)Machine Learning in Materials Science
ResumoWe develop a different Monte Carlo approach applied to the ${A}_{x}{B}_{y}{C}_{1\ensuremath{-}x\ensuremath{-}y}D$ quaternary alloys. Combined with first-principles total-energy calculations, the thermodynamic properties of the $(\mathrm{Al},\mathrm{Ga},\mathrm{In})X$ ($X=\mathrm{As}$, P, or N) systems are obtained and a comparative study is developed in order to understand the roles of As, P, and N atoms as the anion $X$ in the system ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{y}{\mathrm{In}}_{1\ensuremath{-}x\ensuremath{-}y}X$. Also, we study the thermodynamics of specific compositions in which AlGaInN, AlGaInP, and AlGaInAs are lattice matched, respectively, to the GaN, GaAs, and InP substrates. We verify that the tendency for phase separation is always towards the formation of an In-rich phase. For arsenides and phosphides this occurs in general for lower temperatures than for their usual growth temperatures. This makes these alloys very stable against phase separation. However, for nitrides the In and/or Al concentrations have to be limited in order to avoid the formation of In-rich clusters and, even for low concentrations of In and/or Al, we observe a tendency of composition fluctuations towards the clustering of the ternary GaInN. We suggest that this latter behavior can explain the formation of the InGaN-like nanoclusters recently observed in the AlGaInN quaternary alloys.
Referência(s)