Angle-resolved phase-sensitive determination of the in-plane gap symmetry in YBa2Cu3O7−δ

  title={Angle-resolved phase-sensitive determination of the in-plane gap symmetry in YBa2Cu3O7−$\delta$},
  author={John R. Kirtley and Chang C. Tsuei and Ariando and C. J. M. Verwijs and S. Harkema and H. Hilgenkamp},
  journal={Nature Physics},
AbstractUnderstanding the nature of the ground state and its low-lying excitations in the copper oxide superconductors is a prerequisite for determining the origin of high-temperature superconductivity. A superconducting order parameter (that is, the energy gap) with a predominantly dX2−Y2 symmetry is well-established. However, various deviations from a pure d-wave pair state, such as the possibility of Cooper pairing with broken time-reversal symmetry or an admixed dX2−Y2+s pair state, have… Expand
Fully gapped superconductivity in a nanometre-size YBa2Cu3O(7-δ) island enhanced by a magnetic field.
A spectroscopic technique based on an HTS nanoscale device that allows an unprecedented energy resolution thanks to Coulomb blockade effects, a regime practically inaccessible in these materials previously. Expand
Spin-orbit coupling in the superconducting phase and DDW states of high-Tc cuprates
Abstract. The effects of the spin-orbit coupling are considered for the high Tc cuprates with asymmetric superconducting gap (SC) and the d-density wave (DDW) phase due to its vital role in theExpand
Evolution of Pairing Orders between Pseudogap and Superconducting Phases of Cuprate Superconductors
By studying a strongly correlated model at low temperatures, a phase characterized by two kinds of pairing order parameters is obtained with the total momentum of the Cooper pair to be zero and finite and the consequence of breaking symmetry between x and y due to the unidirectional PDW is discussed. Expand
Bulk-sensitive laser-ARPES study on the cuprate superconductor YBa2Cu3O7-δ
Abstract We investigate the bulk superconducting electronic structure in optimally doped YBa 2 Cu 3 O 7 - δ (YBCO) using laser-excited angle-resolved photoemission spectroscopy. The band dispersionsExpand
Universal scaling and pairing symmetry for high-temperature cuprate superconductors
Since the discovery of high-temperature superconductivity in the copper oxides (cuprates), intense research has been devoted to identify universal trends among various physical properties, aimed atExpand
Broken time-reversal symmetry in a SQUID based on chiral superconducting Sr2RuO4
Unconventional superconductors involve not only gauge-symmetry breaking but also orbital- and spin-symmetry breaking. Superconducting Sr2RuO4 is known as a spin-triplet chiral p-wave and aExpand
Spontaneous symmetry breaking at surfaces of d -wave superconductors: Influence of geometry and surface ruggedness
Surfaces of d-wave superconductors may host a substantial density of zero-energy Andreev states. The zero-energy flat band appears due to a topological constraint, but comes with a cost in freeExpand
Broken translational symmetry at edges of high-temperature superconductors
An order parameter is proposed to quantify a phase transition associated with exotic topological properties in high-temperature superconductors hosting such flat bands of midgap Andreev surface states. Expand
Investigation by small-angle neutron scattering of collective vortex behaviour in KFe2As2 and some YBaCuO basedsuperconductors
Results are reported of small-angle neutron scattering studies of the collective vortex behaviour from two overdoped YBa2Cu3O7-d samples, one 90% detwinned and one twin free. The results areExpand
Majorana bound states in magnetic impurity chains: effects of $d$-wave pairing
We consider an atomic chain of magnetic impurities on the surface of a spin-orbit coupled superconductor with a dominating $d$-wave and sub-dominating $s$-wave order parameters. In particular, weExpand


In-Plane Anisotropy of the Penetration Depth in YBa2Cu3O7-x and YBa2Cu4O8 Superconductors.
  • Basov, Liang, +7 authors Timusk
  • Materials Science, Medicine
  • Physical review letters
  • 1995
Measurements of the a-b plane anisotropy of the London penetration depth in high quality, untwinned single crystals of 123 and 124 indicate that superconductivity, at least in the 123 and124 compounds, is not confined to the planes but extends to the chains as well. Expand
Admixtures to d-wave gap symmetry in untwinned YBa2Cu3O7 superconducting films measured by angle-resolved electron tunneling.
The IcRn(theta) dependence is well fitted by 83% dx2-y2-, 15% isotropic s-, and 2% anisotropic s-wave order parameter symmetry, consistent with deltab/deltaa approximately/= 1.5. Expand
Phase-sensitive tests of the symmetry of the pairing state in the high-temperature superconductors-Evidence for d x 2 -y 2 symmetry
Understanding the mechanism responsible for superconductivity in the high-temperature cuprates has been one of the major goals of condensed-matter physicists since the discovery of these excitingExpand
Superconducting gap and strong in-plane anisotropy in untwinned YBa2Cu3O(7-delta).
With significantly improved sample quality and instrumental resolution, this advance allows us to investigate the large a-b anisotropy of the in-plane electronic structure including, in particular, a 50% difference in the magnitude of the superconducting gap that scales with the energy position of the hump feature. Expand
Pairing symmetry in cuprate superconductors
Pairing symmetry in the cuprate superconductors is an important and controversial topic. The recent development of phase-sensitive tests, combined with the refinement of several otherExpand
Phase-sensitive evidence for d-wave pairing symmetry in electron-doped cuprate superconductors
We present phase-sensitive evidence that the electron-doped cuprates Nd(1.85)Ce(0.15)CuO(4-y) (NCCO) and Pr(1.85)Ce(0.15)CuO(4-y) (PCCO) have d-wave pairing symmetry. This evidence was obtained byExpand
Spontaneous breaking of time-reversal symmetry in the pseudogap state of a high-Tc superconductor
It is reported that, for a material in the pseudogap state, left-circularly polarized photons give a different photocurrent from right- Circularly polarization photons, which shows that time-reversal symmetry is spontaneously broken below T*, which therefore corresponds to a phase transition. Expand
Measurements of the anisotropy and temperature dependence of the in-plane energy gap in YBa2Cu3O7- delta using Andreev reflections.
The temperature dependence and the anisotropy of the in-plane energy gap are deduced, and features at eV>2Δ, which appear at harmonics of the gap, and which the observed features as arising from Andreev reflections are interpreted. Expand
The Raman scattering spectra of fully oxygenated twin-free YBa2Cu3O7 crystals have been investigated. In addition to the out-of-plane and the in-plane anisotropy in all Ag phonon lines in the normalExpand
Extending SQUID interferometry beyond the cuprates and beyond d-wave symmetry
Phase-sensitive superconducting quantum interference device (SQUID) interferometry measurements have been instrumental in establishing the d-wave pairing symmetry of the high-temperature cuprates. WeExpand