Theoretical physicist uncovers how twisting layers of a material can generate a mysterious electron-path-deflecting effect

Phys.org  October 4, 2024
Studies of moirĂ© systems have explained the effect of superlattice modulations on their properties, demonstrating new correlated phases. However, most experimental studies have focused on a few layers in two-dimensional systems. Extending twistronics to three dimensions, in which the twist extends into the third dimension, remains underexplored because of the challenges associated with the manual stacking of layers. A team of researchers in the US (University of Pennsylvania, SLAC National Accelerator Laboratory, University of Wisconsin-Madison) studied three-dimensional twistronics using a self-assembled twisted spiral superlattice of multilayered WS2. Their findings showed an opto-twistronic Hall effect driven by structural chirality and coherence length, modulated by the moirĂ© potential of the spiral superlattice. This is an experimental manifestation of the noncommutative geometry of the system. They observed enhanced light–matter interactions and an altered dependence of the Hall coefficient on photon momentum. According to the researchers their model suggests contributions from higher-order quantum geometric quantities to this observation provides opportunities for designing quantum-materials-based optoelectronic lattices with large nonlinearities… read more. TECHNICAL ARTICLE

Illustration and linear optical characterization of the 3D supertwisted spirals of WS2. Credit: Nature volume 634, pages69–73, 18 September, 2024

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