Sum Rules and Interlayer Infrared Response of the High Temperature $YBa2Cu3Oy$ Superconductor in an External Magnetic Field

A. D. LaForge, W. J. Padilla, K. S. Burch, Z. Q. Li, A. A. Schafgans, Kouji Segawa, Yoichi Ando, D. N. Basov.
Sum Rules and Interlayer Infrared Response of the High Temperature $YBa2Cu3Oy$ Superconductor in an External Magnetic Field
Phys. Rev. Lett. 101, 097008 (2008)