Gap anisotropy in the angle-resolved photoemission spectroscopy of Bi2Sr2CaCu2O8+δ

The gap anisotropy in Bi2Sr2CaCu2O8+delta is revisited in the framework of a d-wave scenario in view of the recent angle-resolved photoemission experiment. Based on a tight-binding fit to the normal state dispersion, a detailed analysis of the effects of the inclusion of the next harmonic in the d-wave has been presented. Significant effect has been observed in the superconducting T-c,. The density of states is Linear at the nodes with enhanced weight, caused by a marked increase in the low energy excitations which affect the thermodynamics considerably. The slope of the rho(s)-T curve in the low temperature regime increases and the specific heat reflects the enhanced entropy at low temperatures. The leading edge of the ARPES energy distribution curves have been calculated and found to shift towards higher energy. The effect of scattering by non-magnetic impurities in this context is also outlined. (C) 1999 Elsevier Science B.V. All rights reserved.