Disorder-induced finite center-of-mass momentum Cooper pairing and its consequences to the critical temperature and superconducting gap of overdoped cuprates

Abstract

One of the most studied classes of unconventional high-temperature superconductors is the hole-doped cuprates, where special attention is given to those doped with extra interstitial oxygens. In this context, the formation of spatially inhomogeneous agglomerates of dopant oxygen atoms in the form of nanosized puddles is not only relevant, but also subject of intense recent experimental and theoretical surveys. Following these efforts, in this work we show the consequences of the presence of networks of oxygen puddles in the superconducting state of overdoped cuprates. Starting from the inhomogeneous disordered background brought by the network of puddles, we show that an effective interaction between electrons can be mediated by the local vibrational degrees of freedom of each puddle, but the pairs arising from this interaction have a finite center-of-mass momentum p, thus breaking up the Cooper channel. Furthermore, we derive an analytical expression for the amplitude of the superconducting gap ∆ k in terms of disorder and finite center-of-mass momentum and show that amplitude fluctuations are induced in the superconducting state by the presence of the puddles, where both the gap and the critical temperature are affect and reduced by disorder and finite momentum pairs. Finally, we discuss our findings in the context of networks of superconducting oxygen nano-puddles in cuprates.