posted 6 Aug 2019, 08:50 by info admin
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updated 6 Aug 2019, 08:53
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University of Oxford
Polycyclic Aromatic Hydrocarbons (PAHs) are organic frameworks made of multiple aromatic rings [1]. In PAHs, the open-shell configuration is a resonant structure with the closed-shell one. According to the Clar's aromatic rule, the energy stabilisation provided by formation of additional aromatic rings can compensate for the rupture of carbon bonds, leaving unpaired electrons – the strong delocalisation distributes the spin density all over the molecule. Here we use pulsed electron paramagnetic resonance to investigate the quantum properties of PAHs. I will show how the shape and conjugation length of the carbon framework will play a crucial role in the magnetic properties. As confirmed by the Rabi oscillations, spins on these carbon-based nanostructures can be initialised into an arbitrary superposition of states, making polyciclic aromatic hydrocarbons a candidate for spin qubits in the framework of molecular qubits. We compared our results with the phase memory time of famous qubit candidates in the literature. We state that a toluene solution has larger Tm than those of semiconducting quantum dots above the liquid nitrogen temperature.
[1] Sun, Z. and Wu, J., 2012. Open-shell polycyclic aromatic hydrocarbons. Journal of Materials Chemistry, 22(10), pp.4151-4160. [2] Wedge, C.J., Timco, G.A., Spielberg, E.T., George, R.E., Tuna, F., Rigby, S., McInnes, E.J.L., Winpenny, R.E.P., Blundell, S.J. and Ardavan, A., 2012. Chemical engineering of molecular qubits. Physical review letters, 108(10), p.107204. [3] Li, X., Steel, D., Gammon, D. and Sham, L.J., 2004. Quantum information processing based on optically driven semiconductor quantum dots. Optics and photonics news, 15(9), pp.38-43.
Alessandro Lodi is a first-year PhD student at the University of Oxford in the Lapo Bogani group. He obtained both his BSc and MSc in Chemistry from the University of Modena and Reggio Emilia. Thanks to the Erasmus+Traineeship Program, he spent 10 months in the Bogani group as a MSc student, working on pulsed electron-spin resonance of polycyclic aromatic hydrocarbons. During his stay, appointed a Clarendon Scholarship for pursuing a DPhil program in Materials. Currently, his scientific interests lie in both the fabrication of field-effect transistors using molecular synthesised graphene nanoribbons as conductive channels and their characterisation both at room and millikelvin temperatures. |
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