Negative spin exchange in a multielectron quantum dot
Abstract
By operating a one-electron quantum dot (fabricated between a multielectron dot and a one-electron reference dot) as a spectroscopic probe, we study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition between odd and even occupation number. We observe that the multielectron groundstate transitions from spin-1/2-like to singlet-like to triplet-like as we increase the detuning towards the next higher charge state. The sign reversal in the inferred exchange energy persists at zero magnetic field, and the exchange strength is tunable by gate voltages and in-plane magnetic fields. Complementing spin leakage spectroscopy data, the inspection of coherent multielectron spin exchange oscillations provides further evidence for the sign reversal and, inferentially, for the importance of non-trivial multielectron spin exchange correlations.
Cite
@article{arxiv.1706.01007,
title = {Negative spin exchange in a multielectron quantum dot},
author = {Frederico Martins and Filip K. Malinowski and Peter D. Nissen and Saeed Fallahi and Geoffrey C. Gardner and Michael J. Manfra and Charles M. Marcus and Ferdinand Kuemmeth},
journal= {arXiv preprint arXiv:1706.01007},
year = {2017}
}
Comments
8 pages, including 4 main figures and 2 supplementary figurures