Tuning the electron transport properties of a one-dimensional constriction using hydrostatic pressure

Abstract

Hydrostatic pressure and illumination have been used to investigate electron transport through a clean one-dimensional constriction in a deep two-dimensional electron gas (2DEG) formed at a GaAs/AlxGa1-xAs interface. Up to 20 quantized conductance steps were observed at integer multiples of 2e2/h, as well as a clear additional step (the "0.7 structure") at approximately 0.7x2e2/h. Using both pressure and illumination the electron density in the 2DEG was reduced from 2.14x10(15) m(-2) to 0.6x10(15) m(-2), and a shift in the conductance of the "0.7 structure" towards the spin-split value of e2/h was observed. The density measurements are compared to calculations of the 2D electron density as a function of pressure, obtained by solving the Schrodinger-Poisson equation for the heterostructure. There is also a reversal of the persistent photoconductivity effect at high pressures that cannot be accounted for.