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

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

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.

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T. Valla, T. E. Kidd, J. D. Rameau, H. -J. Noh, G. D. Gu, P. D. Johnson, H. -B. Yang, H. Ding. 2005-12-28. Fine Details of the Nodal Electronic Excitations in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$. https://doi.org/10.1103/physrevb.73.184518

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