Imaging the electron charge density in monolayer MoS2 at the Ångstrom scale
Abstract
Four-dimensional scanning transmission electron microscopy (4D-STEM) has recently gained widespread attention for its ability to image atomic electric fields with sub-Ångstrom spatial resolution. These electric field maps represent the integrated effect of the nucleus, core electrons and valence electrons, and separating their contributions is non-trivial. In this paper, we utilized simultaneously acquired 4D-STEM center of mass (CoM) images and annular dark field (ADF) images to determine the projected electron charge density in monolayer MoS2. We evaluate the contributions of both the core electrons and the valence electrons to the derived electron charge density; however, due to blurring by the probe shape, the valence electron contribution forms a nearly featureless background while most of the spatial modulation comes from the core electrons. Our findings highlight the importance of probe shape in interpreting charge densities derived from 4D-STEM and the need for smaller electron probes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 20, 2023
- Source ID
- 10.1038/s41467-023-39304-9
Entities
People
- Alex Zettl
- Archith Rayabharam
- Arun Majumdar
- Cassandra Huff
- Cong Su
- Eric Pop
- Hao-kun Li
- Joel Martis
- Krishna C. Saraswat
- Marc Jaikissoon
- Narayana R Aluru
- Peter Ercius
- Philipp Pelz
- Ramamoorthy Ramesh
- Sandhya Susarla
- Timothy Paule
- Victoria Chen
- Xintong Xu