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introduction

Intrinsic Josephson Tunnelling between atomic layers in HTS. Fundamental physics + “blue sky” applications (THz spectroscopy, single-electron and quantum devices). microwave properties. Fundamental physics

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introduction

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  1. Intrinsic Josephson Tunnelling between atomic layers in HTS Fundamental physics + “blue sky” applications (THz spectroscopy, single-electronand quantum devices) • microwave properties Fundamental physics + immediate applications Close synergy with “Emerging Device Technologies” –EE CMP includes - “Emerging Device Physics” introduction Electronic properties of HTS and novel superconductors CEG - Science and microwaves 26th Jan 2004

  2. Birmingham early SQUID measurements confirmed electron-pairing in d-wave HTS also first HTS quantum devices and microwave applications current current volts Ij sinf volts Cooper pairs excitations 2D - energy gap Intrinsic tunnelling Intrinsic Josephson Tunnelling between atomic layers in HTS CEG - Science and microwaves 26th Jan 2004

  3. BSCCO-2212 Bi2Sr2CaCu2O8 • electrical anisotropy ~105 • quasi-2d HTc superconductor • d-wave l=2 Cooper pairs Energy gap D(T,B)D(q)~ cos2q line nodes - gap 0 inter-layer quantum tunnnelling BSCCO xtal Intrinsic Josephson Junction Tunnelling in BSCCO CEG - Science and microwaves 26th Jan 2004

  4. BSSCO cleaves atomically flat ~ mm • Ion beam and chemical photolithography • 10 – 50 mm mesa structures • 4-point VI measurements • across 1-50 atomic layers • atomically defined intrinsic JJs Mesa structures CEG - Science and microwaves 26th Jan 2004

  5. 3.5 A m / I 0 4.2K -3.5 -250 V / mV 0 250 Measurement expertise Birmingham measurements Intrinsic tunnelling across individual atomic layers 10 Josephson junctions in series d-wave Cooper pair and quasi-particle tunnelling x x x x x 4-point IV measurements 20 ns resolution tunnelling dynamics. CEG - Science and microwaves 26th Jan 2004

  6. ~100 nmHTS mesa(FIB -Nature + Nano-technology in Engineering) 1 nm Quantum devices Future - quantum physics of atomically-defined structures Charging energy e2/2C >> kT Resistance/junction > Rquantum = h/e2 Intrinsic single-electron array devices Intrinsic Coulomb-blockade array structures Quantum coherence/computing – Q-bits Also THz spectroscopy (ac Josephson) CEG - Science and microwaves 26th Jan 2004

  7. Spintronics(2) Spintronics on individual atomic layers with Chris Muirhead and Mark Colclough V Measure changes in Tc and Josephson current on the top atomic plane CEG - Science and microwaves 26th Jan 2004

  8. Microwaves Microwave physics -HTS and other novel s/c existing 5-year portfolio programme CEG, Dr Rod Ormeno and Tim Barraclough Birmingham facility is unique Very high resolution/sensitivity MHz - 40 GHz 50 mK to room temperature B up to 16T Low T - Tc often ~ 1K High B - Hc2 often ~ 10T CEG - Science and microwaves 26th Jan 2004

  9. B(r) ~ exp(-x/l) m-wave penetration and losses s/c electrons “normal” electrons Penetration and losses What do microwaves tell us? Complex conductivity s(w,T,B) = s1 + i s2 CEG - Science and microwaves 26th Jan 2004

  10. Sr2RuO4 p-wave s/c Cavity measurements Novel dielectric resonator and typical data Measure resonant frequency shifts and Q-values - sub 1mm single crystals Position and width to 50Hz in 10GHz 0 1K CEG - Science and microwaves 26th Jan 2004

  11. Novel materials novel materials -novel pairing- novel physics Organic s/c k-(ET)2Cu(SCN)2 pairing ? heavy fermions UPt3, CeCoIn5pairing ? HTc d-wave pairing MgB2 Tc~38Ks-wave, but 2 energy gaps Strontium Ruthenatep-wave Also conventional s/c Tmeas < 1K hw > kTB measurements CEG - Science and microwaves 26th Jan 2004

  12. Birmingham Microwave programme Physics - fundamental science Electrical Engineering – applications filters for mobile communications front-end filters for radio astronomy - Jodrell Bank Telescope delay lines and signal processingtuneable filters with ferroelectrics EE - Emerging Device Technologies Group Prof Mike Lancaster, Dr Tim Jackson, Dr Anton Velichko + 4 others Synergy with EE Close synergy in research non-linear properties, spin-injection tuning of filters, ferrites, ferro-electrics,dielectrics continued collaboration involving frontier physics EPSRC views collaboration as a major Birmingham strength CEG - Science and microwaves 26th Jan 2004

  13. CEG - Science and microwaves 26th Jan 2004

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