A Thermodynamic Model for Nearest-Neighbor Distributions in Annealed Quaternary Alloys
We focus on the annealing-induced changes of N-centered nearest-neighbor (NN) entironment in Ga1-xlnxNyAs1-y quaternary alloys and present a statistical distributing model of the binary bonds under thermodynamics equilibrium state. The core of this model is the assumption that the phase separation result of equimolar system at T=0 K is “ + ”, in which the effect of strain has been ignored. We propose two mechanisms for annealing: (i) Atomic relaxation lead to a total energy minimum. (ii) The type conversion of bond configuration is the main reason for the remarkable blue shift. Then parameter r, the number of NN In atoms per N atom, is calculated. We find that the theoretical NN distributions strain is in good agreement with former studies. It can be concluded that the blue shift induced by long-time annealing at low temperature is able to be equal with that induced by short-time annealing at higher temperature. The results are close to recent investigations. But an allegorical linear relation between band gap and composition (x, y) is still in question.
L. L. Tang and C. B. Wang, "A Thermodynamic Model for Nearest-Neighbor Distributions in Annealed Quaternary Alloys", Advanced Materials Research, Vols. 383-390, pp. 768-773, 2012