Direct observation of electronic-liquid-crystal phase transitions and their microscopic origin in La1/3Ca2/3MnO3

• Published in: Scientific reports 2016-11, Vol.6 (1), p.37624-37624, Article 37624
• Main Authors: Tao, J., Sun, K., Yin, W.-G., Wu, L., Xin, H., Wen, J. G., Luo, W., Pennycook, S. J., Tranquada, J. M., Zhu, Y.
• Format: Article
• Language: English
• Subjects: 639/766/119/1002; 639/766/119/2795; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Humanities and Social Sciences; MATERIALS SCIENCE; multidisciplinary; Phase transitions; Phase transitions and critical phenomena; Probes; Science; Structure of solids and liquids
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep37624

The ground-state electronic order in doped manganites is frequently associated with a lattice modulation, contributing to their many interesting properties. However, measuring the thermal evolution of the lattice superstructure with reciprocal-space probes alone can lead to ambiguous results with competing interpretations. Here we provide direct observations of the evolution of the superstructure in La 1/3 Ca 2/3 MnO 3 in real space, as well as reciprocal space, using transmission electron microscopic (TEM) techniques. We show that the transitions are the consequence of a proliferation of dislocations plus electronic phase separation. The resulting states are well described by the symmetries associated with electronic-liquid-crystal (ELC) phases. Moreover, our results resolve the long-standing controversy over the origin of the incommensurate superstructure and suggest a new structural model that is consistent with recent theoretical calculations.