Pressure dependence of effective dynamic charge in InxAl1−xAs ternary alloys

• Raman Scattering experiment was performed on InxAl1−xAs under high pressure.
• Effective charge of InAs-like mode increases with increasing pressure for some x.
• Most binary alloys show only decreasing effective charge with increasing pressure.
• The competition between charge transfer and covalent character is responsible for this behavior.

Using Raman scattering data under high pressure, we show that InxAl1−xAs ternary alloys exhibit, depending on In molar fraction x, either decreasing or increasing effective dynamic charge for InAs-like mode with increasing pressure. The variation of the effective dynamic charge in ternary alloy is determined by two factors: (1) the charge transfer between two different vibrating pairs and (2) the tendency to reduce it under lattice contraction in binary case.