Dielectric function of YBCO determined by attenuated total reflection in the mid-infrared (3,392 nm)

Abstract

The real, ε r, and imaginary, ε i, components of the ab-plane dielectric function at 3392 nm of doped thin films of YBa 2Cu 3O 7− δ has been determined from measured attenuated total reflectance data. While ε i, is nearly temperature independent, | ε r| decreases by ∼25% between 85 and 295 K. A strong dependence on doping is observed: the magnitudes of ε r and ε i are both strongly suppressed as delta increases. A generalised Drude analysis shows that the scattering rate increases in the underdoped regime.