Negative Spin Exchange in a Multielectron Quantum Dot.

  title={Negative Spin Exchange in a Multielectron Quantum Dot.},
  author={Frederico Martins and Filip K. Malinowski and Peter D Nissen and Saeed Fallahi and Geoff C. Gardner and Michael J. Manfra and Charles M. Marcus and Ferdinand Kuemmeth},
  journal={Physical review letters},
  volume={119 22},
We use a one-electron quantum dot as a spectroscopic probe to study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition between odd and even occupation numbers. We observe that the multielectron ground-state transitions from spin-1/2-like to singletlike to tripletlike 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… Expand
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