  We have investigated the effects of hydrostatic pressure and compressive
biaxial strain on the $\Gamma$-point energy states of GaN and InN with
zincblende crystal structure via first-principles DFT+HSE06 computation. To
correctly reproduce accepted experimental values of the energy band gap of both
compounds, the procedure includes modified exchange-correlation fractions in
the HSE hybrid functional, changing from the standard value $\alpha=0.25$ to
$\alpha=0.43$ (GaN) and $\alpha=0.40$ (InN). Within this environment, the work
reports on the variation of conduction and valence band edges as functions of
the lattice deformation. In addition, we present fitted expressions describing
the change in the band gap and the spin-orbit splitting energy due to unit cell
size modification. All these parameters are main input quantities in the
description of electronic and optical properties of InN/GaN-based
heterostructures.
