Decoding Spatial Complexity in Strongly Correlated Electronic Systems

TL;DR

This paper develops new methods to decode surface electron structures in strongly correlated materials, revealing that nematic patterns observed on the surface extend throughout the bulk and are influenced by disorder, interactions, and anisotropy.

Contribution

The paper introduces novel decoding techniques that confirm the bulk presence of surface-observed nematic structures in SCES, linking surface patterns to bulk properties.

Findings

Nematic structures persist throughout the bulk of the material.

Pattern formation is influenced by disorder, interactions, and anisotropy.

Surface structures can be indicative of bulk properties.

Abstract

Inside the metals, semiconductors, and magnets of our everyday experience, electrons are uniformly distributed throughout the material. By contrast, electrons often form clumpy patterns inside of strongly correlated electronic systems (SCES) such as colossal magnetoresistance materials and high temperature superconductors. In copper-oxide based high temperature superconductors, scanning tunneling microscopy (STM) has detected an electron nematic on the surface of the material, in which the electrons form nanoscale structures which break the rotational symmetry of the host crystal. These structures may hold the key to unlocking the mystery of high temperature superconductivity in these materials, but only if the nematic also exists throughout the entire bulk of the material. Using newly developed methods for decoding these surface structures, we find that the nematic indeed persists throughout the bulk of the material. We furthermore find that the intricate pattern formation is set by a delicate balance among disorder, interactions, and material anisotropy, leading to a fractal nature of the cluster pattern. The methods we have developed can be extended to many other surface probes and materials, enabling surface probes to determine whether surface structures are confined only to the surface, or whether they extend throughout the material.