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Gap at the Node in UD LSCO Cuprates

Gap at the Node in UD LSCO Cuprates. Yu He SC Meeting Jul 11, 2013. Symmetry argument - w hy nontrivial. Doping dependent nodal gap. A temperature perspective – competing orders?. Connection to polaronic settings in UD LSCO. Conflicting experiments and puzzles.

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Gap at the Node in UD LSCO Cuprates

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  1. Gap at the Node in UD LSCO Cuprates Yu He SC Meeting Jul 11, 2013 • Symmetry argument - why nontrivial • Doping dependent nodal gap • A temperature perspective – competing orders? • Connection to polaronic settings in UD LSCO • Conflicting experiments and puzzles

  2. T-depnodal gap in 2% LSCO 30meV

  3. T-dependence on 7% and 10% LSCO 7% LSCO 10% LSCO TC Temperature (K) 4 5 6 7 8 9 10 11 Sr doping (%) TC

  4. Symmetry argument d+s wave Gap size (meV) Δd fixed at 40meV; line nodes with Δs = 0, 10, 20, 40, 60meV respectively AFM fluctuation can give an i-component Θdeg d+is wave Gap size (meV) W.A. Atkinson et al., PRL 109, 267004 (2012) Θdeg

  5. Doping dependent nodal gap 12% LSCO 10% LSCO antinode node Temperature (K) 0 1 2 3 4 5 6 7 8 9 10 Sr doping (%) 1% LSCO 3% LSCO 5% LSCO 7% LSCO ~60meV ~40meV ~20meV

  6. Conflicting experiments and puzzles Xingjiang: gap not closing up to 150K in La-Bi2201 Our results: nodal gap not closing up to 200K in 2% LSCO SLS: nodal gap closes between 80K and 130K in 7% LSCO Is the competing phase contributing to pairing? Is the competition unique to LSCO or ubiquitous? SC on top of Fully gapped FS?

  7. Conflicting experiments and puzzles UD22 Bi2212 I.M. Visik et al., PNAS 109, 18332(2012)

  8. Summary • In both non-SC and underdoped-SC regime, gap shows minimum at nodal direction • Gap function resembles that from d+is order parameter rather than direct addition of d+s • Nodal gap exists in underdoped LSCO when there is no SC • Nodal gap coexists with SC below 1/8 doping • Beyond 12% Sr-doping, nodal gap vanishes, recovering d-wave SC at node • Nodal gap decreases below Tc when Tc is lower than nodal gap’s driving order onset temperature • Nodal gap closes at some temperature below Tc when Tcis higher than nodal gap’s driving order onset temperature

  9. The End. …and more related background

  10. Phase diagram in LSCO Yoichi Ando et al., Phys. Rev. Lett. PRL 93, 267001 (2004) LSCO: Phase diagram from 2nd derivative of resistivity AFM Spin Glass

  11. ARPES – nodal gap and the struggling history E. Razzoli. et al., PRL 110, 047004 (2013) T. Yoshida et al., J. Phys.: Condens. Matter 19 (2007) 125209 Doping dependence More data: A. Ino et al., PHYSICAL REVIEW B 65, 094504 Inna’s PNAS

  12. Theory and Computation – disorder induced broadening and nodal gap W. Chen et al., PHYSICAL REVIEW B 80, 094519 (2009)

  13. Neutron – spin fluctuation and correlation length In LSCO – long range order vs. short range fluctuation S. Wakimoto et al., PRL 98, 247003 (2007) M. Matsuda et al., Phys. Rev. B 65, 134515 (2002) Neutron Scattering Studies of Antiferromagnetic Correlations in Cuprates, J. Tranquada (Chapter 6) Triangles – commensurate order Circles – incommensurate order Spin wave stiffness Interlayer coupling

  14. Transport – VRH and NNH Jun Tateno, PhysicaC 214 (1993) 377-384

  15. Phase diagram of La-Bi2201 J. Eckstein et al., PRL 96, 107003 (2006) Y. Ando et al., Phys Rev B 67, 104512 (2003) Yoichi Ando et al., Phys. Rev. Lett. PRL 93, 267001 (2004)

  16. Temperature dependence for p=0.55 0.055 With both symmetrization and FD division 12K Oxygen 0.105 1.05 0.84 p 0.03 0.10 3K Nodal gap persists up to 300K No show of data of T>150K b/c ‘disappearance of the coherence peak at high temperatures makes it difficult to quantitatively determine the gap size.’ 0.08 0.07 0.055 0.04

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