Isotope effect on the nodal kink energy in Bi2212
ORAL
Abstract
Using low energy angle resolved photoemission spectroscopy (le-ARPES), we have observed an energy shift of the nodal kink upon substitution of $^{18}$O for $^{16}$O in optimally doped (T$_{c}\sim $92K) Bi2$_{.1}$Sr$_{1.9}$CaCu$_{2}$O$_{8+\delta }$. Studying several samples of each isotope, we find that the kink energy decreases by 3.22 $\pm $ 0.72 meV upon $^{18}$O substitution, in good agreement with the energy shift one would expect from a phononic mode. This strongly supports the view that the nodal dispersion kink arises from electronic coupling to a phonon mode.
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