Nonmonotonic Magnetoresistance of Two-dimensional Electron Systems in the Ballistic Regime

Abstract

We report experimental observations of a novel magnetoresistance (MR) behavior of two-dimensional electron systems in perpendicular magnetic field in the ballistic regime for kB Tτ/>1. The MR grows with field and exhibits a maximum at fields B>1/μ where μ is the electron mobility. As temperature increases, the magnitude of the maximum grows and its position moves to higher fields. This effect is universal: it is observed in various Si- and GaAs-based two-dimensional electron systems. We compared our data with recent theory based on the Kohn anomaly modification in magnetic field and found qualitative similarities and discrepancies. © 2009 The American Physical Society.