Advanced Visualization of Electronic Band Structure in Bulk and Suspended WTe2

Objective

As electronics shrink to atomic scales, silicon-based devices are now approaching fundamental physical and technological limits. At the same time, rapidly growing computing demands, especially in artificial intelligence, drive a steep rise in global energy consumption, conflicting with urgent sustainability goals. Breakthroughs in materials science are needed to enable scalable, low-power devices that exploit quantum phenomena for energy-efficient information processing and transfer. This project, WAVE (WTe2: Advanced Visualization of Electronic Band Structure), addresses this challenge by studying tungsten ditelluride (WTe2). This layered transition metal dichalcogenide, is predicted to host type-II Weyl fermions, elusive quasiparticles with tilted band crossings that enable anisotropic, high-mobility transport. Experimental verification of these quasiparticles has been challenging due to their energy lying above the Fermi level and the limited momentum resolution of conventional techniques. The host group recently developed a faster quasiparticle interference QPI method with significantly improved reciprocal-space resolution, enabling timely detection of elusive quasiparticles. Additionally, a robust 2D-platform for few-to-monolayer WTe2 suspended on nanoporous membranes is developed, eliminating substrate-induced strain and screening effects. This will allow to systematically study how tunable, tip-induced strain affects topological edge states and excitonic insulator phases in suspended WTe2, linking strain to emergent quantum phenomena. To achieve these goals, WAVE integrates advanced nanofabrication at ETH Zurich, low-temperature scanning tunneling microscopy (STM), and newly developed fast-QPI imaging at UZH. WAVE will provide unprecedented insights into quantum phases in low-dimensional materials, paving the way for future strain-engineered, energy-efficient electronic devices and directly contributing to the EU’s strategic green and digital transitions.