Heterostructure design to achieve high quality, high density GaAs 2D electron system with g-factor tending to zero
Abstract
Hydrostatic pressure is a useful tool that can tune several key parameters in solid state materials. For example, the Land\'e g-factor in GaAs two-dimensional electron systems (2DESs) is expected to change from its bulk value g-0.44 to zero and even to positive values under a sufficiently large hydrostatic pressure. Although this presents an intriguing platform to investigate electron-electron interaction in a system with g=0, studies are quite limited because the GaAs 2DES density decreases significantly with increasing hydrostatic pressure. Here we show that a simple model, based on pressure-dependent changes in the conduction band alignment, quantitatively explains this commonly observed trend. Furthermore, we demonstrate that the decrease in the 2DES density can be suppressed by more than a factor of 3 through an innovative heterostructure design.