Unveiling the microscopic origin of the electronic smectic-nematic phase transition in La1/3Ca2/3MnO3

TL;DR

This study provides direct experimental evidence of a microscopic electronic smectic-nematic phase transition in doped manganite, revealing mechanisms involving dislocation proliferation and charge inhomogeneity, crucial for understanding strongly-correlated materials.

Contribution

First direct observation of the smectic-nematic transition in a doped manganite, elucidating microscopic mechanisms behind the phase change.

Findings

Dislocation pairs emerge near the transition temperature.

Transition driven by dislocation proliferation and charge inhomogeneity.

Electronic phase separation occurs in the nematic phase.

Abstract

Electronic-liquid-crystal phases, in which part of the spatial symmetries are broken spontaneously, are considered to play a vital role in interpreting the structure-property relation in strongly-correlated materials. Although electronic-liquid-crystal phases have been inferred in studies of a wide range of materials, the nature of the transition between such phases has received little experimental attention. Here we report the direct observation of an electronic smectic-nematic phase transition in a doped manganite utilizing transmission electron microscopic techniques. We show that, in this case, the transition from the smectic to the nematic phase is driven by two mechanisms: the proliferation of dislocations and the development of mesoscale charge inhomogeneity. We observe the development of dislocation pairs within the commensurate smectic phase on approaching the transition (at 210 +/- 10 K) from below. Above the transition, the incommensurate nematic phase is accompanied by mesoscopic electronic phase separation.