Measurement by antilocalization of interactions between InAs surface electrons and magnetic surface species

Abstract

We show that antilocalization measurements can be used to experimentally study the interactions between InAs surface electrons and local moments of the rare earth ions Sm${}^{3+}$, Gd${}^{3+}$, and Ho${}^{3+}$ on the surface. Magnetic spin-flip scattering and spin-orbit scattering of the accumulation layer electrons are affected by the proximity of the rare earth ions. The spin-flip rate carries information about magnetic interactions. Within the temperature range studied, Sm${}^{3+}$ and Gd${}^{3+}$ yield temperature-independent electron spin-flip rates in proportion to their magnetic moments. In proximity to Ho${}^{3+}$ the InAs electrons however show a spin-flip rate increasing with temperature. We interpret the spin-flip rate due to Ho${}^{3+}$ as resulting from transitions between closely spaced energy levels of the ion on the surface. The experiments also show that the strength of spin-orbit interaction can be modified by the surface species.