Heterostructure design to achieve high quality,high density CaAs 2D electron system with g-factor tending to zero

摘要

Hydrostatic pressure is a useful tool that can tune several key parameters in solid state materials. For example, the Lande g-factor in GaAs two-dimensional electron systems (2DESs) is expected to change from its bulk value gapprox=0.44 to zero and even to positive values under 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.