For In x Ga 1-x As InAs-like GaAs-like Then, we calculate the parameters we need Results Phonon modes (meV) In 0.248 Ga 0.752 AsIn 0.59 Ga 0.41 AsInAs LO 35.3228.74629.74 TO 32.8927.9327.01 ε ∞ 11.52611.28711.7 TO LO TO LO InGaAs/InAs material system