The c-axis optical sum rule and possible new collective mode in LSCO

A. B. Kuzmenko, N. Tombros, H. J. A. Molegraaf +3

We present the c-axis optical conductivity ${\sigma }_{1c}(\omega ,T)$ of underdoped ($x$ = 0.12) and optimally doped ($x$ = 0.15) LSCO from 4 meV to 1.8 eV obtained by a combination of reflect…