Direct imaging of lattice strain-induced stripe phases in an optimally-doped manganite

TL;DR

This study uses high-resolution STM/STS to directly image lattice strain-induced stripe phases in an optimally-doped manganite, revealing the role of lattice strain in charge modulation and phase separation.

Contribution

It demonstrates the formation of insulating and metallic stripe textures driven by lattice strain, challenging the view of electronically homogeneous phases in manganites.

Findings

Stripe phases are formed by competing orbital and charge orders.

Lattice strain mediates long-range electron wave-function overlap.

Stripe phases impede inhomogeneous phase evolution.

Abstract

In a manganite film without quenched disorder, we show texturing in the form of insulating and metallic stripes above and below Curie temperature (Tc), respectively, by high resolution scanning tunneling microscopy/spectroscopy (STM/STS). The formation of these stripes involves competing orbital and charge orders, and are an outcome of overlapping electron wave-functions mediated by long-range lattice strain. Contrary to popular perception, electronically homogeneous stripe phase underlines the efficacy of the lattice strain in bringing about charge density modulation and in impeding the cross-talk between the order parameters, which otherwise evolves inhomogeneously in the form of orbitally-ordered insulating and orbitally disordered metallic phases.