Relevance of Dzyaloshinskii–Moriya spectral broadenings in promoting spin decoherence: a comparative pulsed-EPR study of two structurally related iron( iii ) and chromium( iii ) spin-triangle molecular qubits

Jérôme Robert (1) , Nathalie Parizel (2) , Philippe Turek (2) , Athanassios K Boudalis (2)

1 LJP - Laboratoire Jean Perrin
2 Institut de Chimie de Strasbourg

Spectral broadenings due to Dzyaloshinskii-Moriya interactions (DMI) were assessed with respect to the decoherence they induce through increased spin-spin interactions, as the role of DMI in developing magnetoelectric spin-chirality qubits is gaining recognition. The structurally related spin triangles [Fe 3 O(PhCOO) 6 (py) 3 ]ClO 4 ⋅py (Fe 3) and [Cr 3 O(PhCOO) 6 (py) 3 ]ClO 4 ⋅0.5py (Cr 3) were studied as frozen py-d 5 solutions with various pulsed Electron Paramagnetic Resonance (EPR) spectroscopy experiments, and under identical experimental conditions. Field-swept Hahn echo experiments revealed a match with continuous-wave (CW) spectra, while variable-temperature saturation/inversion recovery and Hahn echo decay experiments were used to extract the thermal evolutions of the spin-lattice relaxation and phase-memory times (T 1 and T m , respectively). Nutation experiments revealed Rabi oscillations demonstrating that the spins of the complexes could be coherently manipulated. Careful comparisons of T M times confirmed hyperfine interactions with the magnetic nuclei of the metal ions as an intrinsic source of decoherence. Comparisons of Rabi damping times revealed that DMI-induced spectral broadenings play a discernible but moderate role as an extrinsic source of decoherence for the nutation experiments and that they are not particularly detrimental to spin manipulations.

Domaines: Chimie de coordination

Jérôme Robert, Nathalie Parizel, Philippe Turek, Athanassios K Boudalis. Relevance of Dzyaloshinskii–Moriya spectral broadenings in promoting spin decoherence: a comparative pulsed-EPR study of two structurally related iron( iii ) and chromium( iii ) spin-triangle molecular qubits. Physical Chemistry Chemical Physics, 2019, 21 (35), pp.19575-19584. ⟨10.1039/c9cp03422f⟩. ⟨hal-02444324⟩