Direct Study of the Nature of Nitrogen Bound States inGaAs1−xPx:N

A new theory in which the observed electronic states in N-doped $\mathrm{Ga}{\mathrm{As}}_{1-x}{\mathrm{P}}_x$ derive from the combination of a long-range disorder and strain-induced nitrogen-associated potential and the usual short-range isoelectronic nitrogen potential is compared with pressure measurements at $x\sim 0.30$ (and with earlier measurements at $x\gtrsim 0.45$). In the composition region $x\sim 0.3$ a strong ${\mathrm{N}}_{\Gamma }-{\mathrm{N}}_X$ interaction is predicted and is observed by pressure measurements.