Martin Wood Complex, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Sonia Conesa Boj, Delft University of Technology
Prof Michael Johnston
Abstract
Engineered van der Waals (vdW) materials hold tremendous promise for revolutionizing condensed matter science and driving innovation in nanoelectronics, nanophotonics, quantum communication, and sensing. These materials can be assembled into a variety of homo- and heterostructures, where strain fields, material combinations, and twist-angle manipulation generate new crystal lattice periodicities (moiré patterns), giving rise to phenomena such as exciton trapping, bandgap modulation, and unconventional superconductivity.
In this talk, I highlight recent progress in the fabrication, analysis, and interpretation of vdW materials in non-trivial configurations beyond planar structures. To achieve this, we exploit recent breakthroughs in advanced Transmission Electron Microscopy (TEM) and related techniques, such as four-dimensional (4D) Scanning Transmission Electron Microscopy (STEM) and Electron Energy Loss Spectroscopy (EELS). We deploy machine learning algorithms originally developed for high-energy particle physics for TEM data analysis, using custom-tailored open-source code developed in-house. This strategy enables to precisely control lattice reconstruction, strain- and defect-engineering, and electrostatic field distributions down to the nanoscale. I showcase key results obtained through this way, including the onset of modulated bandgaps and exciton localisation in MoS2 nanotubes, strain-driven bandgap variations in twisted WS2, and enhanced non-linear optical emission in large-scale arrays of Mo/MoS2 core-shell nanopillars.
Our results illustrate how developing novel material configurations unlocks unique functionalities in vdW homo- and heterostructures, when combined with cutting-edge data processing and interpretation algorithms. This pave the way for pioneering new platforms that advance applications ranging from light sources for quantum communication to low-power electronics.
Zoom - https://zoom.us/j/4862374566