Universal Disorder in Bi2Sr2CaCu2O8+x

TL;DR

This study reveals a universal nanoscale disorder pattern in Bi2Sr2CaCu2O8+x across various doping levels, linking energy scales, spatial excitations, and modulations to a single underlying disordered parameter.

Contribution

It introduces a universal disordered energy scale model for Bi2Sr2CaCu2O8+x, connecting local electronic features with spatial modulations and a single underlying parameter.

Findings

Disorder pattern is universal across doping levels.

Energy scales are linked to spatial excitations.

A single disordered parameter governs LDOS and modulations.

Abstract

The cuprates contain a range of nanoscale phenomena that consist of both LDOS(E) features and spatial excitations. Many of these phenomena can only be observed through the use of a SI-STM and their disorder can be mapped out through the fitting of a phenomenological model to the LDOS(E). We present a study of the nanometer scale disorder of single crystal cryogenically cleaved samples of Bi2Sr2CaCu2O8+x whose dopings range from p = 0.19 to 0.06. The phenomenological model used is the Tripartite model that has been successfully applied to the average LDOS(E) previously. The resulting energy scale maps show a structured patchwork disorder of three energy scales, which can be described by a single underlying disordered parameter. This spatial disorder structure is universal for all dopings and energy scales. It is independent of the oxygen dopant negative energy resonances and the interface between the different patches takes the form of a shortened lifetime pseudogap/superconducting gap state. The relationship between the energy scales and the spatial modulations of the dispersive QPI, static q1* modulation and the pseudogap shows that the energy scales signatures in the LDOS(E) are tied to the onset and termination of the spatial excitations. The static q1* modulations local energy range is measured and its signature in the LDOS(E) is the kink, whose number of states are modulated with a wave vector of q1*. This analysis of both the LDOS(r,E) and the spatial modulations in q-space show a picture of a single underlying disordered parameter that determines both the LDOS(E) structure as well as the energy ranges of the QPI, q1* modulation and the pseudogap states. This parameter for a single patch can be defined by the Fermi surface crossing of the parent compound anti-ferromagnetic zone boundary for a model homogeneous superconductor with the same electronic properties as the patch.