Fine Details of the Nodal Electronic Excitations in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$

Valla, T.; Kidd, T. E.; Rameau, J. D.; Noh, H. -J.; Gu, G. D.; Johnson, P. D.; Yang, H. -B.; Ding, H.

Fine Details of the Nodal Electronic Excitations in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$

Authors

Description

Very high energy resolution photoemission experiments on high quality samples of optimally doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ show new features in the low-energy electronic excitations. A marked change in the binding energy and temperature dependence of the near-nodal scattering rates is observed near the superconducting transition temperature, $T_C$. The temperature slope of the scattering rate measured at low energy shows a discontinuity at ~$T_C$. In the superconducting state, coherent excitations are found with the scattering rates showing a cubic dependence on frequency and temperature. The superconducting gap has a d-wave magnitude with negligible contribution from higher harmonics. Further, the bi-layer splitting has been found to be finite at the nodal point.
5 pages, 4 figures