[2E09-15] Two-Dimensional Materials 

4:30 PM - 5:00 PM JST(7:30 AM - 8:00 AM UTC)

[2E14【依頼講演】] Direct observation of electronic band structures in van der Waals assemblies

*Masato Sakano¹ (1. The University of Electro-Communications (Japan))

Stacking two-dimensional materials into van der Waals assemblies is a powerful method to create artificial materials by manipulating crystal symmetry. Controlling spatial inversion symmetry is key to governing exotic electronic and spintronic phenomena. We developed a fabrication process for van der Waals structures suitable for micro-focused angle-resolved photoemission spectroscopy, allowing us to visualize how symmetry engineering alters the electronic structure. We demonstrate this with two examples. First, in WTe₂, controlling the layer number induces an insulator-to-semimetal transition (2-3 layers) and a distinct odd-even effect in spin-splitting, driven by layer-dependent structural asymmetry. Second, in ReSe₂, we artificially break inversion symmetry by stacking centrosymmetric monolayers in an anti-parallel configuration, confirmed by second harmonic generation and observed in the band structure. These results establish a robust methodology for designing novel electronic structures by precisely controlling layer number and stacking, paving the way for new phenomena in Berry curvature physics and spintronics.

Password required to view