Electron momentum densities in GaxIn1-xAsySb1-y probed by positrons

Momentum densities of electron-positron pairs in cubic GaxIn1-xAsySb1-y lat tice matched to GaSb and InAs are studied for the first time to the best of our knowledge, with the aim of investigating the disorder and substrate ef fects on these quantities in the materials for interest. The electron wavef unction is calculated using the pseudopotential band model under the virtua l crystal approximation with and without incorporating the effects of compo sitional variations. The calculations of the positron wavefunction is made in an identical manner, employing the point-core approximation for the ioni c potential. It is found that while the electron-positron momentum densitie s in GaxIn1-xAsySb1-y at x = 0.50 are sensitive to the compositional disord er, they are not altered by the change of substrate.