Presentation Information
[1G09]Direct observation of electronic band structures in van der Waals assemblies
*Masato Sakano1 (1. Graduate School of Informatics and Engineering, The University of Electro-Communications)
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 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 electronic structures by precisely controlling layer number and stacking, paving the way for novel phenomena in Berry curvature physics and spintronics.