Experimental Measurements of Electron-Electron Interactions in Two-Dimensional Electron Systems

Electron–electron (e-e) interactions have a fundamental role in determining the quasiparticle lifetime in Fermi liquid theory, but do not affect electron mobility because the interactions conserve the total system momentum. Hence precision measurements were only recently achieved [e.g. 1,2]. Here we investigate e-e interactions using variable temperature (4-36 K) transverse magnetic focusing (TMF) measurements [1] on a high-mobility 2D electron system in a GaAs/AlGaAs heterostructure with conjoined high-resolution kinetic simulations. The ballistic nature of TMF brings out the importance of e-e interactions as dominant scattering mechanism in high-mobility materials, demonstrating that TMF can be used as a precision technique for probing e-e interactions. The measurements show deviations from the theory by Giuliani & Quinn, which is followed only up to a multiplicative constant. Deviations have also been noted in other recent experimental work. The possible origin of the systematic variance of the theory will be discussed.