Spatially correlated incommensurate lattice modulations in an atomically thin high-temperature Bi_{2.1}Sr_{1.9}CaCu_{2.0}O_{8+{\delta}} superconductors

TL;DR

This study uses nano X-ray diffraction to image incommensurate lattice modulations in ultra-thin cuprate superconductors, revealing strain-induced patterns that influence their electronic properties.

Contribution

It demonstrates the ability to visualize and control lattice modulations in atomically thin high-temperature superconductors using nano X-ray diffraction.

Findings

Long-range and short-range ILM domains are spatially correlated.

In 2-unit cell samples, wavevectors become anti-correlated with directional patterns.

Strain tuning can induce static charge density waves.

Abstract

Strong variations in superconducting critical temperatures in different families of the cuprate perovskites, even with similar hole doping in their copper-oxygen planes, suggest the importance of lattice modulation effects. The one-dimensional incommensurate lattice modulation (ILM) of Bi_2Sr_2CaCu_2O_{8+y}, with the average atomic positions perturbed beyond the unit cell, offers an ideal test ground for studying the interplay between superconductivity and the long-range incommensurate lattice fluctuations. Here we report Scanning nano X-ray Diffraction (SnXRD) imaging of incommensurate lattice modulations in Bi_{2.1}Sr_{1.9}CaCu_{2.0}O_{8+{\delta}} Van der Waals heterostructures of thicknesses down to two-unit cells. Using SnXRD, we probe that the long-range and short-range incommensurate lattice modulations in bulk sample surface with spatial resolution below 100 nm. We find that puddle-like domains of ILM of size uniformly evolving with dimensionality. In the 2-unit cell thin sample, it is observed that the wavevectors of the long- and short-range orders become anti-correlated with emerging spatial patterns having a directional gradient. The emerging patterns, originated by tiny tuning of lattice strain, induce static mesoscopic charge density waves. Our findings thus demonstrate that the strain can be used to tune and control the electromagnetic properties of two-dimensional high-temperature superconductors.