Precision measurement of electron-electron scattering in GaAs/AlGaAs using transverse magnetic focusing

• Published in: Nature communications Vol. 12; no. 1; p. 5048
• Main Authors: Gupta, Adbhut, Heremans, J. J., Kataria, Gitansh, Chandra, Mani, Fallahi, S., Gardner, G. C., Manfra, M. J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19-08-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/1130/2798; 639/766/119/995; Aluminum gallium arsenides; Amplitudes; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Computer engineering; Cyclotrons; electronic and spintronic devices; electronic properties and materials; Electrons; Geometry; Heterostructures; Humanities and Social Sciences; MATERIALS SCIENCE; Mobility; multidisciplinary; Physics; Scattering; Science; Science & Technology - Other Topics; Science (multidisciplinary); Simulation; Solid state physics; Temperature dependence; Vortices
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25327-7

Electron-electron (e-e) interactions assume a cardinal role in solid-state physics. Quantifying the e-e scattering length is hence critical. In this paper we show that the mesoscopic phenomenon of transverse magnetic focusing (TMF) in two-dimensional electron systems forms a precise and sensitive technique to measure this length scale. Conversely we quantitatively demonstrate that e-e scattering is the predominant effect limiting TMF amplitudes in high-mobility materials. Using high-resolution kinetic simulations, we show that the TMF amplitude at a maximum decays exponentially as a function of the e-e scattering length, which leads to a ready approach to extract this length from the measured TMF amplitudes. The approach is applied to measure the temperature-dependent e-e scattering length in high-mobility GaAs/AlGaAs heterostructures. The simulations further reveal current vortices that accompany the cyclotron orbits - a collective phenomenon counterintuitive to the ballistic transport underlying a TMF setting.
Electron-electron scattering plays a crucial role in many solid state phenomena; however, the direct measurement of electron-electron scattering length is challenging. Here, the authors use transverse magnetic focusing to measure this quantity in high-mobility GaAs/AlGaAs heterostructures.