Study of Lattice Constant and Bulk Modulus in Zincblende InGaN Using Local Density Approximation and Generalized Gradient Approximation

Numerical analysis based on first-principles calculation is applied to study the lattice constant, bulk modulus, and the pressure derivative of the bulk modulus of ternary zincblende InGaN. Results obtained using local density approximation (LDA) and generalized gradient approximation (GGA) for the exchange–correlation energy are compared. Comparing calculated results with available experimental results for binary InN and GaN, it is found that overbinding in LDA results in underestimation of the lattice constant and overestimation of the bulk modulus, but underbinding in the GGA results in overestimation of the lattice constant and underestimation of the bulk modulus. The theoretical results, on average, are equally accurate and applicable from GGA as from LDA.