Probing the spin states of three interacting electrons in quantum dots

Andrea Gamucci, Vittorio Pellegrini, Achintya Singha, Aron Pinczuk, Loren N. Pfeiffer, Kenneth W. West, Massimo Rontani

Published 2011-09-22Version 1

We observe a low-lying sharp spin mode of three interacting electrons in an array of nanofabricated AlGaAs/GaAs quantum dots by means of resonant inelastic light scattering. The finding is enabled by a suppression of the inhomogeneous contribution to the excitation spectra obtained by reducing the number of optically-probed quantum dots. Supported by configuration-interaction calculations we argue that the observed spin mode offers a direct probe of Stoner ferromagnetism in the simplest case of three interacting spin one-half fermions.