Magnetoresistively detected electron spin resonance in low-density two-dimensional electron gas in GaAs-AlGaAs single quantum wells

Electron spin resonance (ESR) is a natural candidate for quantum bit manipulation, provided that the confinement of a small number of electrons in a sufficiently small volume can be achieved. An important step is the development of low carrier density materials and structures in which the electron spins are isolated and can be controlled by ESR. We report on the realization of three low-density (n/sub 1/=1.77/spl times/10/sup 10/, n/sub 2/=4.5/spl times/10/sup 10/, and n/sub 3/=9/spl times/10/sup 10/ cm/sup -2/ without the help of a gate to deplete the channel) two-dimensional electron systems in GaAs-AlGaAs single quantum wells (QWs) and on the magnetoresistively detected electron spin resonance (MDESR) measurements in these samples. The MDESR has been characterized at /spl nu/=1 and /spl nu/=3 and the current intensity, microwave power, and temperature dependence have been studied. The structures that have been investigated represent the lowest density single QW samples in which MDESR has been detected. The implications of detection of the MDESR at such low electron density to coupled quantum-dot spin device technology will be presented.