Microwave and millimeter wave spectroscopy in the slightly hole-doped ladders of Sr${}_{14}$Cu${}_{24}$O${}_{41}$

H. Kitano, R. Inoue, T. Hanaguri +6

We have measured the temperature- and frequency dependence of the microwave and millimeter wave conductivity ${\sigma }_1(T,\omega )$ along both the ladder (c-axis) and the leg (a-axis) directio…