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Nuclear Spin, I | Sensing & Controlling Single Spins in Silicon Andrew Dzurak University of New South Wales [email protected] ANFF – AFOSR Program Review Washington D.C., 30 April - 4 May 2012 ANFF @ UNSW • 3 x EBL Systems (Raith, FEI ...) • Highest Concentration in Australia • Sub-10nm Features • Silicon MOS Process Line TiAuPd ANFF-NSW: Key Research Areas Silicon Nanoelectronics Silicon Photovoltaics Biomedical Devices (eg. Bionics, Si Biosensors) Telecomms (Nano-photonics) Quantum Information Technologies www.anff.org.au Conventional computing … … must confront some serious issues Cost of Fab $60B $50B $40B 360B $20B ? $10B $0B 1992 1995 1998 2001 2004 2007 2010 Year Quantum computing … could well be the solution Conventional Quantum |1> Computer Computer 0 , 1 |0 >, |1 > |0> bits qubits Quantum state of a two-level system |0> |1> Quantum Information Science Data Security Decryption National Security National Security Financial Services Intelligence e-Commerce Killer? Apps High Performance Semiconductors Computing Database Searching Integrated Circuits Bioinformatics Sensors Modeling & Design Nano-structuring Code Decryption • Public key encryption (RSA-129) is (almost) uncrackable. Basis of public secure comms today • A full-scale (few hundred qubits) quantum computer could crack RSA-129 in seconds (Peter Shor – 1994) • Obvious applications in national and global security High Performance Computing • Simulation (modeling) & database searching • Existing supercomputers now under strain • Application areas: Nuclear weapons simulation Rapid data search – Security services Biotechnology – modeling (new reagents & pharma) – – searching (bioinformatics) Advanced R&D – modeling (commercial, govt) Internet Search Engines – q-Google ? • Timescale for 1 0 0 0 qubits: 1 0 – 3 0 years Next Generation Integrated Circuits • Spin-off or pathway technologies potentially provide nearer term applications than QC per se • Eg: Single atom nanotechnologies • Possible applications: Next generation transistors - extending Moore’s Law (to 2020) - single atom transistors Transistors per chip 109 ? 108 • Current world semiconductor Pentium 80786 7 10 Pro 80486 market $ 2 0 0 billion Pentium 106 80386 80286 105 8086 104 8080 4004 103 1970 1975 1980 1985 1990 1995 2000 2005 2010 Year The first quantum computers … Spin-based Qubits: GaAs Quantum Dots GaAs Spin Qubits: David Reilly (U. Sydney) • US-EU-JAPAN-AUST collaboration: Multi-qubit operations with electron spins Funded by US iARPA Spin Qubits in Silicon • ARC Centre of Excellence for Quantum Computation & Communication Technologies (CQCCT) A$24.5M for 2011-17 B=2T Phosphorus Donor Spin Qubits in Silicon • Long Coherence Times in Silicon at 1K: Nuclear – mins Electron – ms-s • Scalable • Industry “Compatible” Transport Interaction B=2T Hollenberg et al, PRB (2006) Single Atom Nanotechnologies: Top-Down & Bottom-Up 1 nm Single Atom Nanoelectronics : Top Down UNSW U Melbourne D.N. Jamieson et al. Summary SPIN QUBITS IN SILICON • 31P Electron Spin Qubit Single-Shot Readout Single Electron ESR • 31P Nuclear Spin Qubit Single-Shot Readout Single Atom NMR • Next Steps ... Co-Workers, CQC2T Programs & Sponsors Integrated Silicon Nano-Spintronics: ASD Quantum Spin Control: Andrea Morello Deterministic Atom Implant: David Jamieson UNSW University of Melbourne Jarryd Pla Jessica van Donkelaar, Juan-Pablo Dehollain Dr Changyi Yang, Andrew Alves, Jeff McCallum, Lloyd Hollenberg Rachpon Kalra Fahd Mohiyaddin Dr John Morton, Oxford Henry Yang Malcolm Carroll, Rajib Rahman ... Sandia Jason Cheng Gerhard Klimeck, Purdue Chandni Ravi Dr Nai Shyan Lai Dr Mikko Möttönen, Dr Kuan Yen Tan, Dr Kok Wai Chan Aalto, Finland Dr Fay Hudson Dr Wee Han Lim, NUS Dr Arne Laucht Dr Floris Zwanenburg, Twente Summary SPIN QUBIT READOUT • 31P Electron Spin Qubit High-Fidelity (>90%) Single-Shot Readout Electron Spin T1e ~ 6 s A. Morello et al., Nature 467, 687 (2010) Readout Device: Si-MOS SET S. Angus, A.J. Ferguson, A.S. Dzurak & S. Angus, A.J. Ferguson, A.S. Dzurak & R.G. Clark, R.G. Clark, Nano Lett. (2007) Appl. Phys. Lett. (2008) Spin Readout Device for P donors 3 donors in the 3050 nm “active area” 18 in total P-donor & SET Island are Tunnel-Coupled A. Morello et al., Phys. Rev. B 80, 081307(R) (2009) TEM Device Fabrication n++ n++ Al source Al AlxOy top gate SiO 20 nm 2 Silicon 100 nm plunger 10 mm drain n++ n++ Spin-to-Charge Conversion donor reservoir & SET island drain B Vtop gate Vplunger Charge Sensing: 100% Contrast ISET donor N-1 N N+1 Electron on P-donor ISET = 0 (Coulomb blockade) P-donor Empty ISET > 0 Vtop gate ISET Vtop gate Vplunger Electron Spin Qubit: Readout Protocol Andrea Morello et al. Phys. Rev. B 80, 081307R (2009) Hans Huebl et al., Phys. Rev B 81, 235318 (2010) Andrea Morello et al., Nature 467, 687 (2010) B-Dependence of Spin Lifetime: T1 10 ) 1 - Valley (s repopulation 1 - 1 -1 5 T T1 B 1 Relaxation rate Relaxation T1 6 s 0.1 1 2 3 4 5 6 Magnetic field B (T) A. Morello et al., Nature 467, 687 (2010) High Fidelity Spin Readout BW = 120 kHz Rise/fall time 3 ms 92% Visibility A. Morello et al., Nature 467, 687 (2010) Summary SPIN QUBIT CONTROL & READOUT • 31P Electron Spin Qubit Single Electron ESR • 31P Nuclear Spin Qubit Single-Shot Readout Fidelity > 99.9% Jarryd Pla Juan Dehollain Kuan Yen Tan Wee Han Lim David Jamieson John Morton Andrea Morello Qubit Gate Operations: P-Donor ESR & NMR 1. Qubit Initialize: | 2. Spin Rotation: | + | Electron spin down NMR and ESR pulses 3. Qubit Readout: initialization electron spin flips conditional to nuclear state | or | Projective single-shot measurement | | 31P:Si P-Donor B0 RF1 Electron/Nuclear Bac mw1 mw2 Spin Levels RF2 = Electron Spin, S | = Nuclear Spin, I | H = gmBB0Sz – nB0Iz + A I S On-Chip Microwave Line No Resonator Broadband to 50 GHz On-chip Balun Lithographic transition CPW CPS Local Spin Resonance + Single-Shot Readout Single P Donor ESR load ESR pulse readout B 160 VP V3 120 V2 80 i ESR Spin-Up Counts Spin-Up 40 I SET 1.610 1.612 1.614 1.616 B (T) time Local ESR + Single-Shot Readout Single P Donor ESR load ESR pulse readout B 160 VP V3 120 V2 80 i ESR Spin-Up Counts Spin-Up 40 I SET 1.610 1.612 1.614 1.616 B (T) time Local ESR + Single-Shot Readout Single P Donor ESR load ESR pulse readout B 4.08 mT 160 VP V3 120 V2 i 80 ESR Spin-Up Counts Spin-Up Spin-Up Counts Spin-Up 40 I SET 1.610 1.612 1.614 1.616 B (T) time Local ESR + Single-Shot Readout 31P Nuclear Spin Qubit: Single-Shot Readout B = 1.78986 T 0 | | 0.3 0.2 mw1 mw2 0.1 Up Fraction - | 0.4 | 0.2 = Electron Spin Electron Spin Electron 0.0 49.50 49.55 49.60 49.65 = Nuclear Spin µw (GHz) 31P Nuclear Spin Qubit: Single-Shot Readout Pulse Sequence: B0 = 1.079 T = 29.891 GHz 256 repetitions mw1 260 ms per measurement mw2 = 30.005 GHz read read read read mw2 mw2 mw1 mw1 | | 140 120 mw1 mw2 100 80 | 60 | 40 electron spin-up counts spin-up electron 20 0 0 60 120 180 240 300 360 420 > 7 hours …! Time (min) 31P Nuclear Spin Qubit: Single-Shot Readout B.E. Kane, Nature read read read read mw2 mw2 mw1 mw1 393, 133 (1998) B=2T 140 120 | 100 | 80 60 mw1 mw2 40 electron spin-up counts spin-up electron 20 0 | 40 45 50 55 60 | Time (min) T1n ~ mins (cf. hrs in bulk) 31P Nuclear Spin Qubit: Readout Fidelity Readout Fidelity > 99.9% 140 120 0.09 Off-resonance 1.0 100 On-resonance Off-res. fidelity 0.8 On-res. fidelity 80 0.06 Visibility 60 0.6 40 0.4 electron spin-up counts spin-up electron 0.03 Probability 20 0.2 0.000 Fidelity / Visibility 0.0 40 45 50 55 60 Time (min) 0.0 0.2 0.4 0.6 0.0 0.2 0.4 0.6 0.8 1.0 Spin-Up Fraction Spin-Up Fraction Threshold Coherent Control: Electron Spin Qubit – Rabi Oscillations T ~ 150 ns; -pulse Fidelity = 57% load coherent pulse readout Measurement Fidelity = 79% 180 10 dBm 160 7 dBm VP 140 V3 120 V2 1 dBm Spin-Up Counts Spin-Up 100 tp 0.0 0.5 1.0 1.5 i rabi 4 t (ms) p 3 I SET 2 time Rabi Frequency (MHz) Rabi 1 1 2 3 P1/2 (mW1/2) Coherent Electron Spin Control: Hahn Echo 1.0 Decoherence Mechanisms: 0.8 29 Spectral Diffusion, Si Single P Donor: 0.6 B-Field Fluctuations T2e ~ 200 µs 0.4 Cf. Bulk: 0.2 T2e ~ 240 µs Norm. Echo Intensity Echo Norm. Gordon and Bowers, PRL 1, 368 (1958) 0.0 0.0 0.5 1.0 1.5 Delay (ms) Spectral Diffusion in natSi 28Si,30Si Lattice 29Si o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 31P o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 28 T2e > 1 s in Si [A.M.
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