30º WSe2 bilayer proven a tunable quasicrystals
•In large-twist angle bilayers, one obtains either a quasicrystal (30º) with 12-fold rotational symmetry without translational symmetry or a periodic moiré crystal (21.8º); their properties are drastically
•Their properties are drastically different: any two points (e.g. K and Q valleys in two layers) in Brillouin zone can be brought arbitrarily close via higher order Umklapp scattering in quasicrystals
•By applying a vertical E field, one can further align the energy of the K and Q valleys in the separate layer, leading to hybridization and a gap oppening
•With an increasing E field, one exciton resonance (Xb) evolves to exciton doublets (Xh) from the hybridization gap.
•Surprisingly, trion disappears with the increasing E field, attributed to evidence of quasicrystal potential driven localization as illustrated.
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Center for Dynamics and Control of Materials
This MRSEC brings together researchers from across science and engineering to create materials with new atomic-scale structures and functionalities, and to develop approaches for actively controlling and reconfiguring materials in real time.