Electrical Detection of Electron Spin Resonance in Fe/n-GaAs

Abstract

A magnetic field applied to a collection of spins splits up and down spins into two distinct energy states. Application of an additional transverse field at a resonant frequency drives transitions between these states in a phenomenon known as electron spin resonance (ESR). Here, detection of ESR is attempted in a system of spins in n-GaAs. While ESR in GaAs has been detected optically in the past, here purely electrical injection and detection is attempted with a three-terminal measurement device. The ESR spin signal in this system is modeled with a computer simulation. Two ESR measurement schemes are developed and attempted. The schemes employ a data taking procedure which significantly reduces the effects of nuclear spin accumulation. A coil mounted on the device is able to successfully drive nuclear magnetic resonance (NMR) but does not produce a large enough radiofrequency (RF) field to induce measureable ESR.