Direct Visualization of Incommensurate Charge-Lattice Order in Correlated Oxides

ORAL

Abstract

The strong coupling between charge, spin, and lattice generates complex correlated phases and, in many cases, ordered patterns that break the spatial symmetries of the crystal. Charge-order stripes are particularly noteworthy because they alter electronic transport, compete with unconventional superconductivity, or spawn novel magnetic orders. As demonstrated by various real space probes, mapping striped electronic modulations locally is a powerful approach for visualizing stripe formation, observing defects and excitations, and discerning broken symmetries. Direct, atomic-scale measurements of lattice degrees of freedom, however, are lacking. Here, we use cryogenic scanning transmission electron microscopy (STEM) to map picometer-scale lattice displacements associated with charge-ordering in manganites. We directly visualize temperature-dependent nanosocale inhomogeneity and the interplay between commensurate and incommensurate modulations. In particular, the real space structure of incommensurate charge order suggests a strong tendency to lattice-locked modulations interspersed with phase defects. These cryogenic STEM measurements reveal a novel methodology for exploring lattice coupling in other correlated systems such layered nickelates and transition-metal dichalcogenides.

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Presenters

  • Ismail El Baggari

    Cornell University, Department of Physics, Cornell University

Authors

  • Ismail El Baggari

    Cornell University, Department of Physics, Cornell University

  • Benjamin Savitzky

    Department of Physics, Cornell University

  • Alemayehu Admasu

    Department of Physics & Astronomy , Rutgers University, Rutgers University

  • Jaewook Kim

    Rutgers University, Physics, Rutgers Univesity, Department of Physics & Astronomy , Rutgers University

  • Sang-Wook Cheong

    Rutgers University, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Physics, Rutgers University, Physics and Astronomy, Rutgers University, Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Physics and Astronomy, Rutgers Univ., Rutgers Univ, Physics, Rutgers Univesity, Department of Physics, Rutgers University, Physics and Astronomy, Rutgers Center for Emergent Materials, Department of Physics & Astronomy , Rutgers University

  • Robert Hovden

    University of Michigan, Materials Science and Engineering, University of Michigan, Materials Science & Engineering, University of Michigan

  • Lena Kourkoutis

    Cornell University, School of Applied & Engineering Physics, Cornell University