title: Room-Temperature Quantum Coherence and Rabi Oscillations in Vanadyl Phthalocyanine: Toward Multifunctional Molecular Spin Qubits.
abstract: Here we report the investigation of the magnetic relaxation and the quantum coherence of vanadyl phthalocyanine, VOPc, a multifunctional and easy-processable potential molecular spin qubit. VOPc in its pure form (1) and its crystalline dispersions in the isostructural diamagnetic host TiOPc in different stoichiometric ratios, namely VOPc:TiOPc 1:10 (2) and 1:1000 (3), were investigated via a multitechnique approach based on the combination of alternate current (AC) susceptometry, continuous wave, and pulsed electron paramagnetic resonance (EPR) spectroscopy. AC susceptibility measurements revealed a linear increase of the relaxation rate with temperature up to 20 K, as expected for a direct mechanism, but τ remains slow over a very wide range of applied static field values (up to ∼5 T). Pulsed EPR spectroscopy experiments on 3 revealed quantum coherence up to room temperature with T(m) ∼1 μs at 300 K, representing the highest value obtained to date for molecular electronic spin qubits. Rabi oscillations are observed in this nuclear spin-active environment ((1)H and (14)N nuclei) at room temperature also for 2, indicating an outstanding robustness of the quantum coherence in this molecular semiconductor exploitable in spintronic devices.
authors: Dipartimento di Chimica "Ugo Schiff" & INSTM RU, Università degli Studi di Firenze , Via della Lastruccia 3, I50019 Sesto Fiorentino (Firenze), Italy.
authors: Matteo
authors: M
authors: Atzori
authors: Dipartimento di Chimica "Ugo Schiff" & INSTM RU, Università degli Studi di Firenze , Via della Lastruccia 3, I50019 Sesto Fiorentino (Firenze), Italy.
authors: Lorenzo
authors: L
authors: Tesi
authors: Dipartimento di Chimica & NIS Centre, Università di Torino , Via P. Giuria 7, I10125 Torino, Italy.
authors: Elena
authors: E
authors: Morra
authors: Dipartimento di Chimica & NIS Centre, Università di Torino , Via P. Giuria 7, I10125 Torino, Italy.
authors: Mario
authors: M
authors: Chiesa
authors: Dipartimento di Chimica "Ugo Schiff" & INSTM RU, Università degli Studi di Firenze , Via della Lastruccia 3, I50019 Sesto Fiorentino (Firenze), Italy.
authors: Lorenzo
authors: L
authors: Sorace
authors: Dipartimento di Chimica "Ugo Schiff" & INSTM RU, Università degli Studi di Firenze , Via della Lastruccia 3, I50019 Sesto Fiorentino (Firenze), Italy.
authors: Roberta
authors: R
authors: Sessoli