Phenomenology of Photoemission Lineshapes of High Tc Superconductors

TL;DR

This paper introduces a phenomenological self-energy model to analyze photoemission data of high Tc superconductors, revealing doping-dependent behaviors of the superconducting gap and pseudogap phenomena.

Contribution

It provides a simple model to extract key electronic properties from photoemission data, highlighting the doping and temperature dependence of the superconducting gap and pseudogap.

Findings

Rapid suppression of scattering rate below Tc across doping levels

Doping-dependent temperature behavior of the superconducting gap

Pseudogap filling-in described by T-Tc broadening

Abstract

We introduce a simple phenomenological form for the self-energy which allows us to extract important information from angle resolved photoemission data on the high Tc superconductor Bi2212. First, we find a rapid suppression of the single particle scattering rate below Tc for all doping levels. Second, we find that in the overdoped materials the gap Delta at all k-points on the Fermi surface has significant temperature dependence and vanishes near Tc. In contrast, in the underdoped samples such behavior is found only at k-points close to the diagonal. Near (pi,0), Delta is essentially T-independent in the underdoped samples. The filling-in of the pseudogap with increasing T is described by a broadening proportional to T-Tc, which is naturally explained by pairing correlations above Tc.