APS Logo

Imaging domains and defects in the stacking of few-layer and twisted CrI<sub>3</sub>

ORAL

Abstract

Different lateral shifts of the stacked monolayers in CrI3 lead to different magnetic ground states, with a rhombohedral-symmetry stacking resulting in ferromagnetic layer ordering, and a monoclinic-symmetry stacking leading to antiferromagnetic layer ordering. Here we explore the structural arrangements found as the CrI3 thickness is systematically reduced to the monolayer limit using 4D-STEM electron diffraction and atomic resolution imaging. We find that CrI3 flakes from bilayer to 50 nanometer thickness remain in a monoclinic stacking when cooled to 95 K. However, the monoclinic group allows for multiple variants -- arising from 120 degree stacking rotations both in-layer and between neighboring CrI3 layers -- and we observe a rich assortment of stacking orders and domains, as well as moirés. We show that these stacking rotations can change as a function of temperature. The observed vertical superposition of monoclinic variants in few-layer to bulk CrI3 flakes may present as an overall three-fold symmetry to macroscopic-averaged measurement, but can be recognized by atomic resolution imaging.

–

Presenters

  • Ariana Ray

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

Authors

  • Ariana Ray

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

  • Yu-Tsun Shao

    Applied and Engineering Physics, Cornell University

  • Yang Xu

    Purdue University, Cornell University, NY, USA, Applied and Engineering Physics, Cornell University, Cornell University

  • Nikhil Sivadas

    Applied and Engineering Physics, Cornell University

  • Tingxin Li

    Applied and Engineering Physics, Cornell University, Cornell University

  • Zefang Wang

    Cornell University, Applied and Engineering Physics, Cornell University

  • Jie Shan

    Cornell University, School of Applied and Engineering Physics and Department of Physics, Cornell University, Cornell University, NY, USA, Physics, Cornell University, Case Western Reserve University

  • Kin Fai Mak

    Cornell University, School of Applied and Engineering Physics, Cornell University, Cornell University, NY, USA, Applied and Engineering Physics, Cornell University

  • David Anthony Muller

    Cornell University, School of Applied and Engineering Physics, Cornell University, Applied and Engineering Physics, Cornell University, School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA