Pressure and composition dependence of thermodynamic properties of zinc-blende AlyGa1-yAs alloy

The moment method in statistical mechanics is applied to study the thermodynamic properties of the zinc-blende AlyGa1-yAs compound. The lattice parameter, isothermal bulk modulus, specific heats at the constant volume and constant pressure of the zinc-blende AlyGa1-yAs crystal are investigated in detail as functions of pressure and Al composition up to 10 GPa at room temperature. Numerical calculations have been performed using the many-body Pearson-Takai-Halicioglu-Tiller potential to describe atomic interactions in the AlyGa1-yAs system. Our work shows that the lattice parameter and specific heats of the AlyGa1-yAs alloy increase almost linearly with the Al composition. Nevertheless, when pressure goes up, while lattice parameter and specific heats decrease gradually, the isothermal bulk modulus increases drastically. Present results can be used as reference data for future experiments and theoretical works. Furthermore, this research proposes the potential of statistical moment method on investigation of thermodynamic and mechanical properties of ternary alloys.