%0 Journal Article
%T Sharp low energy feature in single-particle spectra due to forward scattering in $d$-wave cuprate superconductors
%A Seung Hwan Hong
%A Jin Mo Bok
%A Wentao Zhang
%A Junfeng He
%A X. J. Zhou
%A Chandra M. Varma
%A Han-Yong Choi
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevLett.113.057001
%X There is an enormous interest in renormalization of quasi-particle (qp) dispersion relation of cuprate superconductors both below and above the critical temperature $T_c$ because it enables determination of the fluctuation spectrum to which the qps are coupled. A remarkable discovery by angle-resolved photoemission spectroscopy (ARPES) is a sharp low energy feature (LEF) in qp spectra well below the superconducting energy gap but with its energy increasing in proportion to $T_c$ and its intensity increasing sharply below $T_c$. This unexpected feature needs to be reconciled with $d$-wave superconductivity. Here, we present a quantitative analysis of ARPES data from Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (Bi2212) using Eliashberg equations to show that the qp scattering rate due to the forward scattering impurities far from the Cu-O planes is modified by the energy gap below $T_c$ and shows up as the LEF. This is also a necessary step to analyze ARPES data to reveal the spectrum of fluctuations promoting superconductivity.
%U http://arxiv.org/abs/1306.3731v3