Superconductivity and the c Axis Spectral Weight of High-Tc Superconductors
L. B. Ioffe,
A. J. Millis
The temperature dependence of the c axis
spectral weight (frequency integral of the interplane conductivity) of
high transition temperature (high-Tc)
superconductors is shown to be a probe of thermal and quantal
fluctuations of the phase of the superconducting order parameter. The
behavior of underdoped cuprates is shown to be a natural consequence of
superconducting pairing without long-ranged phase coherence. Very
underdoped cuprates are found to have strong phase fluctuations, even
for temperatures much less than the transition temperature.
Department of Physics and Astronomy, Rutgers University,
Piscataway, NJ 08854, USA.
E-mail: ioffe{at}physics.rutgers.edu (L.B.I.) and
millis{at}physics.rutgers.edu (A.J.M.)