R. Buhleier et al., ANOMALOUS BEHAVIOR OF THE COMPLEX CONDUCTIVITY OF Y1-XPRXBA2CU3O7 OBSERVED WITH THZ SPECTROSCOPY, Physical review. B, Condensed matter, 50(13), 1994, pp. 9672-9675
We have measured the complex conductivity of Y1-xPrxBa2Cu3O7 single-cr
ystal thin films using coherent THz spectroscopy. We obtain directly t
he London penetration depth, the plasma frequency omega(p), and the qu
asiparticle scattering rate 1/tau. We find that 1/tau drops rapidly wi
th temperature below T(c) in all the superconducting samples, implying
that this is a signature of high-T(c) superconductivity. omega(p) dec
reases with increasing chi, indicating that Pr takes mobile carriers f
rom the CuO planes. Both the THz and dc conductivity yield evidence fo
r the opening of a spin gap above T(c).