WS₂ layers show nonlinear phase changes in electron ptychography
Researchers compared monolayer, bilayer and trilayer regions of WS₂ in one specimen using electron ptychography. The measured phase of tungsten columns rose about 13.2% from one to two layers, but only 4.7% from two to three.
Source review period: 2026-10-09
Published: · Updated:
The source does not state the event date; the period shown is the source review period.
The phase reconstructed from diffraction patterns recorded as an electron probe scans a sample can reveal atomic-scale electrostatic potential. Its interpretation is affected by specimen thickness, multiple scattering and overlap between projected atomic columns. The team used different thickness regions in a twisted trilayer WS₂ specimen as an internal reference within the same field of view.
Mean tungsten-column phase rose about 13.2% from the monolayer region to the bilayer, but only 4.7% from the bilayer to the trilayer. Short-range projected W-W overlap added roughly 8–9%, while W-S overlap had little effect. The measurements show that phase does not simply rise linearly with layer count and provide a benchmark for interpreting phase-based potential maps.
Data
Measurements reported by the study
The table reports only findings within this study’s experimental or model scope.
| Approximate increase in mean W-column phase from monolayer to bilayer | 13.2 | Approximate relative change measured under the same acquisition and reconstruction conditions in one specimen; it is not a linear increase with layer count. |
| Increase in mean W-column phase from bilayer to trilayer | 4.7 | Relative increase measured in the same specimen under the same conditions; short-range projected W-W overlap can also affect phase. |
Methodology
Quantity and scope are taken from the methods and results of the first arXiv version dated 9 October 2026; they should not be generalized beyond the study.
Updated:
Subjects and places
Subject proposals
- Science and technologySuggested
- Preserved editorial category/topic; broad candidate onlyarxiv.org ↗
Geographic references
Only source-provided geographic references are shown. Opening an external map is optional. Optional story maps use OpenStreetMap. Opening a map sends your IP address and this site’s address to the map provider; location data remains readable as text without loading the map.
- China · Place role: Coverage · Place type: Country or area · Location precision: RegionalEvidence
- Explicit preserved editorial country/region; no city or national centroid inferredarxiv.org ↗