Light-induced long-ranged disorder effect in ultradilute two-dimensional holes in GaAs heterojunction-insulated-gate field-effect-transistors

Comparing the results of transport measurements of strongly correlated two-dimensional holes in a GaAs heterojunction-insulated-gate field-effect-transistor obtained before and after a brief photoillumination, the light-induced disorder is found to cause qualitative changes suggesting altered carrier states. For charge concentrations ranging from 3× 10¹⁰ down to 7× 10⁸cm^-2, the post-illumination hole mobility exhibits a severe suppression for charge densities below 2× 10¹⁰cm^-2 while almost no change for densities above. The long-ranged nature of the disorder is identified. The temperature dependence of the conductivity is also drastically modified by the disorder reconfiguration from being nonactivated to activated.