Electron spin coherence near room temperature in magnetic quantum dots

Abstract

We report on an example of confined magnetic ions with long spin coherence near room temperature. This was achieved by confining single Mn 2+ spins in colloidal semiconductor quantum dots (QDs) and by dispersing the QDs in a proton-spin free matrix. The controlled suppression of Mn-Mn interactions and minimization of Mn-nuclear spin dipolar interactions result in unprecedentedly long phase memory (T M ∼8μs) and spin-lattice relaxation (T 1 ∼10ms) time constants for Mn 2+ ions at T=4.5K, and in electron spin coherence observable near room temperature (T M ∼1μs).