Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 66: Spintronics / Quantum Information: Vacancies in Diamond and SiC (jointly with HL)
TT 66.7: Talk
Friday, March 15, 2013, 11:15–11:30, H14
Spin polarisation mechanism in nitrogen-vacancy and related colour centres of diamond — Lachlan Rogers1, Neil Manson2, and •Fedor Jelezko1 — 1Institut für Quantenoptik, Universität Ulm, Ulm, Deutschland — 2Laser Physics Centre, Australian National University, Canberra, Australia
Optically induced spon polarisation of the negatively charged nitrogen vacancy centre in diamond (NV−) has been known for a considerable time but there has not been a satisfactory account of how it arises. This lack of explanation is of concern because spin polarisation is the key unique property that allows the centre to function as a room temperature qubit. An optical emission band with ZPL at 1042 nm is understood to arise from a transition between spin-singlet levels which lie between the triplet ground and excited states. We report properties of the singlet levels obtained using spectroscopic techniques on the 1042 nm band. Importantly, we resolve the long-standing uncertainty over the order of these singlets. This improved understanding of the singlet system leads to a tentative description of the physical mechanism for spin polarisation in the NV− centre.
This raises the tantalising possibility of engineering "designer" colour centres for specific applications. For instance, the neutral NV0 centre is known to have a metastable level between its ground and excited states. Manipulating it to open the intersystem crossing from this level back to the ground state would likely give rise to optically induced spin polarisation, opening a second solid-state optically-controlled qubit in diamond.