First-principles investigation of bowing parameter in zinc-blendeSc_xGa_1−xN

Abstract

We present first-principles calculations of the structural and electronic properties of binary GaN, ScN and Sc x Ga 1−x N alloys in the zinc-blende structure using pseudopotential plane-wave method within the density functional theory. The alloys are described by considering configurations in 16-atom supercells, corresponding to 2 × 2 × 2 conventional cubic cells. The lattice parameter, bulk modulus, bulk modulus derivation, the energy band gap and bowing parameter are obtained as a function of Sc concentration for ternary alloys Sc x Ga 1−x N . Our studies focus on the concentration dependence of the electronic band structure and bowing parameter of these alloys. We found that x composition affects strongly bowing parameter and the band gap increases with increasing Sc concentration for Sc x Ga 1−x N in the zinc-blende structure. The results also show that the energy band gap and bowing parameter of the Sc x Ga 1−x N alloys can be obtained by a third-order polynomial equation, E gap (x) = −2.56x 3 + 4.29714x 2 − 0.94857x + 1.83429 eV and b(x) = −72.61x 3 + 117.7x 2 − 70.27x + 16.08 eV, respectively.

Analysis of phase stability, elastic, electronic, thermal, and optical properties of Sc1-xYxN via ab initio methods

“…For the zinc-blende (B3) phase of both binary compounds, it is observed that our results obtained for lattice parameter (a) are very close to the theoretical data. Also, our calculated values of bulk modulus are in good agreement with the results given in the ref [56] and [30] for both binary compounds respectively. Consequently, for concentrations x=0.25, 0.5, and 0.75, none of the measured /theoretical results are available in the literature for comparison.…”