Interlayer Conductivity in the Superconductor Tl-Ba-Cu-O: Energetics and Energy Scales

TL;DR

This study investigates the c-axis electrodynamics of Tl-Ba-Cu-O superconductors, revealing kinetic energy changes at the superconducting transition through infrared spectroscopy and sum rule analysis.

Contribution

It provides new insights into the energy scales and kinetic energy changes associated with superconductivity in Tl-Ba-Cu-O, especially contrasting optimally doped and overdoped samples.

Findings

Kinetic energy decreases below Tc in optimally doped crystals.

No significant kinetic energy change in overdoped samples.

Spectral weight shifts indicate energy scale differences between doping levels.

Abstract

We report on infrared studies of the c-axis electrodynamics of Tl-Ba-Cu-O (Tl-2201) crystals. A sum rule analysis reveals spectral weight shifts that can be interpreted as a kinetic energy change at the superconducting transistion. In optimally doped crystals, showing an incoherent normal state response, the kinetic energy is lowered at T < Tc, but no significant change is found in the over-doped samples, which have more coherent conductivity at T > Tc.