Anomalous oxygen isotope effect on the in-plane FIR conductivity of detwinned YBa2Cu3${}^{16,18}$O${}_{6.9}$

C. Bernhard, T. Holden, A. V. Boris +6

We observe an anomalous oxygen isotope effect on the a-axis component of the far-infrared electronic response of detwinned YBa2Cu3${}^{16,18}$O${}_{6.9}$. For ${}^{18}$O a pronounced low…