The Effect of Intra-Layer Bonding on Electron-Optical Phase Images of Few-Layer WSe2

Abstract

The quantitative analysis of electron-optical phase images recorded using off-axis electron holography often relies on the use of computer simulations of electron propagation through a sample. However, simulations that make use of the independent atom approximation are known to overestimate experimental phase shifts by approximately 10%, as they neglect bonding effects. Here, we compare experimental and simulated phase images for few-layer WSe2 . We show that a combination of pseudopotentials and all-electron density functional theory calculations can be used to obtain accurate mean electron phases, as well as improved atomic-resolution spatial distribution of the electron phase. The comparison demonstrates a perfect contrast match between experimental and simulated atomic-resolution phase images for a sample of precisely know thickness. The low computational cost of this approach makes it suitable for the analysis of large electronic systems, including defects, substitutional atoms and material interfaces.

References in corpus (5)

• Optimized norm-conserving Vanderbilt pseudopotentials
• Atomically thin p-n junctions with van der Waals heterointerfaces
• Electrically Tunable Excitonic Light Emitting Diodes based on Monolayer WSe2 p-n Junctions
• Single donor ionization energies in a nanoscale CMOS channel
• Hybrid sensors based on colour centres in diamond and piezoactive layers

Cited by in corpus (4)

• Efficient first principles simulation of electron scattering factors for transmission electron microscopy
• $\text{ab initio}$ description of bonding for transmission electron microscopy
• Autocorrected Off-axis Holography of 2D Materials
• Quantitative atom counting of Zn and O atoms by atomic resolution off-axis and in-line holography