We demonstrate an electrically controlled high-spin (S=5/2) to low-spin (S=1/2) transition in a three-terminal device incorporating a single Mn2+ ion coordinated by two terpyridine ligands. By adjusting the gate-voltage we reduce the terpyridine moiety and thereby strengthen the ligand-field on the Mn-atom. Adding a single electron thus stabilizes the low-spin configuration and the corresponding sequential tunnelling current is suppressed by spin-blockade. From low-temperature inelastic cotunneling spectroscopy, we infer the magnetic excitation spectrum of the molecule and uncover also a strongly gate-dependent singlet-triplet splitting on the low-spin side. The measured bias-spectroscopy is shown to be consistent with an exact diagonalization of the Mn-complex, and an interpretation of the data is given in terms of a simplified effective model.
@article{arxiv.0912.2640,
title = {Electrical manipulation of spin states in a single electrostatically gated transition-metal complex},
author = {Edgar A. Osorio and Kasper Moth-Poulsen and Herre S. J. van der Zant and Jens Paaske and Per Hedegard and Karsten Flensberg and Jesper Bendix and Thomas Bjornholm},
journal= {arXiv preprint arXiv:0912.2640},
year = {2015}
}