Coexistence of the Pseudogap and the Superconducting Gap Revealed by the c-Axis Optical Study of YBa2(Cu1-xZnx)3O7-δ

To address the issue of the pseudogap in the superconducting state of the high temperature superconducting cuprates, we studied the temperature dependent redistribution of the spectral weight in the \(c\)-axis polarized optical spectra for underdoped YBa2(Cu1-xZnx)3O7-δ single crystals with \(x = 0\), 0.007, 0.012, and 0.04. It was found that for Zn substituted samples, the spectral weight transfer to the high energy region, which characterizes the pseudogap state, continues even below the superconducting transition temperature (\(T_{\text{c}}\)), indicating the coexistence of the pseudogap and the superconducting gap. Moreover, the observation of the pseudogap in the Zn-doped non-superconducting sample gives evidence that the pseudogap is not a precursor of superconductivity.

[1]  T. Kondo,et al.  Disentangling Cooper-pair formation above the transition temperature from the pseudogap state in the cuprates , 2010, 1005.5309.

[2]  L. Taillefer,et al.  Broken rotational symmetry in the pseudogap phase of a high-Tc superconductor , 2009, Nature.

[3]  Willie J Padilla,et al.  Magnetic field-induced modification of superfluid density and interplane spectral weight in YBa$_2$Cu$_3$O$_y$ , 2009 .

[4]  B. Keimer,et al.  Evidence for two separate energy gaps in underdoped high-temperature cuprate superconductors from broadband infrared ellipsometry. , 2008, Physical review letters.

[5]  Y. Toda,et al.  Direct observation of the coexistence of the pseudogap and superconducting quasiparticles in Bi2Sr2CaCu2O8 + y by time-resolved optical spectroscopy. , 2008, Physical review letters.

[6]  N. Momono,et al.  4a×4aelectronic charge order enhanced in the inhomogeneous pseudogap state ofBi2Sr2CaCu2O8+δ , 2007 .

[7]  R. Liang,et al.  Evaluation of CuO 2 plane hole doping in YBa 2 Cu 3 O 6 + x single crystals , 2005, cond-mat/0510674.

[8]  D. Basov,et al.  Signatures of bilayer splitting in the c-axis optical conductivity of double layer cuprates , 2004 .

[9]  T. Holden,et al.  Approximate tight-binding sum rule for the superconductivity-related change of c-axis kinetic energy in multilayer cuprate superconductors , 2002, cond-mat/0207511.

[10]  M. Izumi,et al.  Effects of Zn substitution on the superconductivity and pseudogap in HgBa 2 CuO 4 + δ with various doping levels , 2002 .

[11]  R. Laughlin,et al.  Hidden order in the cuprates , 2000, cond-mat/0005443.

[12]  Y. Fukuzumi,et al.  Zn-doping effect on thec-axis charge dynamics of underdoped high-Tccuprates , 2000 .

[13]  C. Varma.  PSEUDOGAP PHASE AND THE QUANTUM-CRITICAL POINT IN COPPER-OXIDE METALS , 1999 .

[14]  Millis,et al.  Superconductivity and the c axis spectral weight of high-T(c) superconductors , 1999, Science.

[15]  S. Tajima,et al.  Zn-substitution effects on the optical conductivity in YBa2Cu3O7-delta crystals: Strong pair breaking and reduction of in-plane anisotropy , 1998 .

[16]  T. Dahm,et al.  Charge-density-wave and superconductivity d-wave gaps in the Hubbard model for underdoped high-T-c cuprates , 1997 .

[17]  Larkin,et al.  Muon Spin Relaxation Studies of Zn-Substitution Effects in High-Tc Cuprate Superconductors. , 1996, Physical review letters.

[18]  Tajima,et al.  Optical Study on Phonon Anomalies and Spin Gap in YBa2(Cu1-xZnx)3O6.6. , 1996, Physical review letters.

[19]  T. Timusk,et al.  The pseudogap state in high- superconductors: an infrared study , 1996 .

[20]  Williams,et al.  Suppression of the Superconducting Condensate in the High-Tc Cuprates by Zn Substitution and Overdoping: Evidence for an Unconventional Pairing State. , 1996, Physical review letters.

[21]  Alexandrov,et al.  Coherent ab and c Transport Theory of High-Tc Cuprates. , 1996, Physical review letters.

[22]  A. Tsvetkov,et al.  Transverse optical plasmons in layered superconductors , 1996, cond-mat/9609155.

[23]  Miyamoto,et al.  Doping and temperature dependence of c-axis optical phonons in YBa2Cu3Oy single crystals. , 1995, Physical review. B, Condensed matter.

[24]  R. Liang,et al.  Optical phonons polarized along the c axis of YBa2Cu3O6+x, for x = 0.5 → 0.95 , 1995, cond-mat/9508027.

[25]  Uchida,et al.  Effect of Zn doping on charge transport in YBa2Cu3O7-y. , 1995, Physical review. B, Condensed matter.

[26]  V. J. Emery,et al.  Importance of phase fluctuations in superconductors with small superfluid density , 1995, Nature.

[27]  Y. Shiohara,et al.  Continuous crystal growth of YBa2Cu3O7−x by the modified top-seeded crystal pulling method , 1993 .

[28]  P. Anderson,et al.  Interlayer Tunneling and Gap Anisotropy in High-Temperature Superconductors , 1993, Science.

[29]  H. Alloul,et al.  Correlations between magnetic and superconducting properties of Zn-substituted YBa2Cu3O6+x. , 1991, Physical review letters.