Doping dependence of gap inhomogeneities at Bi2Sr2CaCu2O8+δ surfaces

We study the inhomogeneity of the pairing gap near the surface of Bi2Sr2CaCu2O8+δ due to interstitial oxygen dopants. Within the slave boson mean-field theory of a disordered t–t′–J model, we identify three aspects of the oxygen dopants related to inhomogeneity: (i) the superexchange interaction is locally enhanced in the vicinity of oxygen dopants, which enhances the local pairing gap and reduces the coherence peak; (ii) oxygen dopants donate holes into the CuO2 plane, which reduces the spinon density of states and hence the average gap at large doping; and (iii) holes are locally attracted to the vicinity of oxygen dopants, which causes an impurity bound state and further reduces the coherence peak. The interplay of these mechanisms simultaneously explains the locally enhanced pairing gap around oxygen dopants and the reduction of average gap with increasing oxygen concentration, as observed by scanning tunneling microscopy.

[1]  Jungseek Hwang,et al.  Bosons in high-temperature superconductors: an experimental survey , 2011, 1105.0726.

[2]  T. Tohyama,et al.  Enhanced pairing correlations near oxygen dopants in cuprate superconductors. , 2010, Physical review letters.

[3]  H. Kandpal,et al.  Modulation of pairing interaction in Bi 2 Sr 2 CaCu 2 O 8 + δ by an O dopant: A density functional theory study , 2010, 1006.2014.

[4]  F. Vernay,et al.  Impact of an oxygen dopant in Bi2Sr2CaCu2O8+δ , 2009 .

[5]  R. Valentí,et al.  Effect of dopant atoms on local superexchange in cuprate superconductors: A perturbative treatment , 2008, 0809.2919.

[6]  T. Tohyama,et al.  Origin of the spatial variation of the pairing gap in bi-based high temperature cuprate superconductors. , 2008, Physical review letters.

[7]  A. Pasupathy,et al.  Electronic Origin of the Inhomogeneous Pairing Interaction in the High-Tc Superconductor Bi2Sr2CaCu2O8+δ , 2008, Science.

[8]  M. Gabay,et al.  Field-induced local moments around nonmagnetic impurities in metallic cuprates , 2007, 0710.5747.

[9]  A. Pasupathy,et al.  Visualizing pair formation on the atomic scale in the high-Tc superconductor Bi2Sr2CaCu2O8+δ , 2007, Nature.

[10]  M. Mierzejewski,et al.  Inhomogeneity-induced enhancement of the pairing interaction in cuprate superconductors. , 2007, Physical review letters.

[11]  H. Ding,et al.  Correlating off-stoichiometric doping and nanoscale electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O8+delta. , 2007, Physical review letters.

[12]  L. Capriotti,et al.  Gap-inhomogeneity-induced electronic states in superconducting Bi2Sr2CaCu2O(8+delta). , 2006, Physical review letters.

[13]  H.-P. Cheng,et al.  Local electronic structure near oxygen dopants in BSCCO-2212: a window on the high-Tc pair mechanism? , 2006, cond-mat/0601157.

[14]  Jinho Lee,et al.  Atomic-Scale Sources and Mechanism of Nanoscale Electronic Disorder in Bi2Sr2CaCu2O8+δ , 2005, Science.

[15]  P. Hirschfeld,et al.  Dopant-modulated pair interaction in cuprate superconductors. , 2005, Physical review letters.

[16]  G. Aeppli,et al.  Antiferromagnetic order induced by an applied magnetic field in a high-temperature superconductor , 2002, Nature.

[17]  H. Ding,et al.  Inhomogeneous d-wave superconducting state of a doped Mott insulator , 2001, cond-mat/0107004.

[18]  P. Fournier,et al.  Inherent inhomogeneities in tunneling spectra ofBi2Sr2CaCu2O8−xcrystals in the superconducting state , 2001, cond-mat/0101251.

[19]  Lee,et al.  Flux phases in the t-J model. , 1992, Physical review. B, Condensed matter.

[20]  Lee,et al.  Gauge theory of the normal state of high-Tc superconductors. , 1992, Physical review. B, Condensed matter.

[21]  Liu,et al.  Superexchange mechanism and d-wave superconductivity. , 1988, Physical review. B, Condensed matter.

[22]  Hirschfeld,et al.  Mean-field theory of high-Tc superconductivity: The superexchange mechanism. , 1987, Physical review. B, Condensed matter.