Determination of ordering effects on GaInP pressure coefficients

We report the determination of pressure coefficients for ordered and disordered GaInP samples measured in the same diamond anvil cell experiment at 10 K. Results are compared to measurements using substrate calibration and data available in the literature. Using previous theoretical calculations and experimental work we propose a linear model based on the band-gap reduction with ordering to calculate pressure coefficients. To date this is the only available method to quantifying this change. All layers measured were grown nominally lattice matched to GaAs.