Towards quantum simulator based on nuclear spins at room temperature B. Naydenov and F. Jelezko C. Müller, Xi Kong, T. Unden, L. McGuinness J.-M. Cai and M.B. Plenio Institute of Theoretical Physics, Uni Ulm In collaboration with: S. Pezzagna and J. Meijer, Uni Leipzig A. Stacey M. Markham, E6 Ltd. J. Du, Hafei
Slide 2 Outline Controlling single spins nitrogen-vacancy center (NV) in diamond NMR with single spin sensitivity Approaches towards a quantum simulator using fluorine spins Speeding up 2D NMR experiments Summary and Outlook
Slide 3 Quantum simulator on the diamond surface Diamond 111-surface F-F (long range dipole) interaction (6.8 khz nearest neighbor) Fluorographene Diamond 100-surface Cai, Retzker, Jelezko, Plenio. Nature Physics 9, 168 (2013)
Slide 4 Single defects in diamond Nitrogen Vacancy 3E E=hc/638n m Color centers in diamond. Point defects NV, NE8, TR12, SiV and a long list Single defects in a crystalline matrix. Atomic emitter can be shrunk to nm sized Photostablity electrons don t escape! 3A vacancies 800 C 10 µm Production with ion implantation N+ ions Meijer et al., APL 87, 261909 (2005)
Slide 5 Spin properties of NV ms 1 0 mw Fluorescence, a. u. 3E Optically Detected Magnetic Resonance ES 1A 1 3A 0 2800 GS (ground state) H ZFS DS z2 E S x2 S y2 2850 2900 2950 MW frequency, MHz Single spin manipulation Spin polarization in ground state ms=0 by and read out at room optical pumping temperature! Encoding ms=0 and ms=1 as bright A. Gruber et al., Science 276, 2012 (1997) and dark state F. Jelezko, et.al, Phys. Rev. Lett. 92, 76401 (2004)
Slide 6 Coherent spin manipulation Laser 532 nm initialize ms=0 3 s read-out MW pulse Excited-state MW pulse duration ( s) MW effective 2-level system by Zeeman splitting
Pulse Sequences Free Induction Decay (FID) and Hahn echo Spin locking
Slide 8 NMR with few nuclear spins
Slide 9 Single spin spectrometer using NV The basics idea
Slide 10 The NMR Spectrometer
Slide 11 Diamond spin as NMR sensor Use of NV centers as near field antenna for NMR, ESR with nanoscale resolution e- spin sensor nn ne Nuclear spins nn n e Classical noise First detection of external nuclear spins With nanoscale resolution Staudacher et al., Science, 339, 561 (2013) Mamin et al., Science 339, 557 (2013)
Slide 12 The Pulse Sequence - XY8-N Quantum Lock-In Amplifier T. Gullion et al., JMR 89, 479 (1990) S. Kotler et al. Nature 473, 61 (2011)
Slide 13 Nuclear Spins inside the diamond Nuclear spins in a frozen core, strong interaction Kolkowitz, PRL 109, 137601 (2012) Zhao, N. et al. Nature Nanotechnology 7 (2012) Taminiau, T. H. et al. PRL 109, 137602 (2012) nn ne ne 1 T2 e e- spin sensor nn ne Nuclear spins Single nuclear spins resolved, frequency shift in NV field gradient
Slide 14 Creating shallow NVs Implantation of 2.5 kev N+ ions Average depth 4 nm 99.999% 12C diamond. erage distance between 13C > 4nm Low dose N+ implant 3x108 ion/cm2 Average distance between Nitrogen dopants > 500 nm
Slide 15 Mapping the NVs Identification of shallow NV centers via spin noise technique Distance from the surface 1.9 nm for most shallow NV, T2 < 10 µs NV 1: Distance = 2.2 nm Signal = 27-28 1H spins NV 6: Distance = 1.92 nm Signal = 21-22 1H spins NV 7: Distance = 2.2 nm Signal = 27-28 1H spins
Slide 16 Strong coupling regime Polarization not required Utilize NV magnetic gradient to isolate individual nuclei based on their hyperfine shift Also image position relative to NV center Quantum interaction vs classical magnetic field measurement Strongest 29Si-29Si interaction (0.17 khz) Coupling to NV 2 khz
Slide 17 29 Detection of Si nuclei in SiO2 Signal agrees with numerical detection of 5 to 10 29Si nuclei
Slide 18 Contributing nuclear spins About 7 29Si nuclei give 70 % of the signal
Slide 19 Single nuclear spin sensitivity 5 nm3 volume NV Contributing nuclei
Slide 20 2D NMR Correlation Spectroscopy (COSY) Polar. /2 /2 /2 Readout
Slide 21 Frequency Domain full data set
Slide 22 Frequency Domain less data 20 % of the data 10 % of the data
Slide 23 Shallow NVs - problems Implantation with E 1impl =2.5keV T2 measurement T2 = 5,6 μs Implantation with E 2impl =1.25keV Implantation with E 2impl =1.25keV
Slide 24 Increase of Creation Yield by Surface Termination CF4 Plasma: Yield: 0.1% Yield: 0.5%
Slide 25 Oxygen Termination O2 Plasma: Oxygen Terminated Surface : NVs : 1739 Yield : 0.4601% Fluorine Terminated Surface: NVs : 1960 Yield : 0.5185%
Slide 26 Stability and Properties of Implanted NVs T2 measurement before Plasma: T2 = 5,6 μs T2 measurement after Fluorination: T2 = 5,7 μs C. Osterkamp et al. APL 103, 193118 (2013)
Slide 27 Very nice but it did not work! We could not detect the fluorine nuclear spin
Slide 28 New Fluorination Method Using SF6 plasma No oxygen peak!
Slide 29 Fluorinated graphene alternative? Optical picture of diamond surface with graphene Appl. Phys. A 82, 377 384 (2006)
Slide 30 Conclusion and Outlook We can detect few nuclear spins at room temperature! Different implementations of a small nuclear spin cluster Implementation of matrix completion
Slide 31 Thank you!
CPMG (XY) sensing Shallow NV suffer from surface noise (T2 < 10 µs) Use of high order dynamical decoupling (XY 8-N) H 0 L I Z H1 ( L A) I Z BI X Two different nuclear spin quantization axes 1 2 0 1 U 0 exp ih 0 exp ih1 exp ih 0 U 0 exp ih1 exp ih 0 exp ih1 The nuclear spin is rotated differently depending on the electron subspace Polarization of nuclear spins is not required
Distance Measurement