NCAFM2023 Programme Booklet

Thursday 1000-1020

ATOMICALLY-PRECISE QUANTUM ANTIDOTS VIA VACANCY SELF-ASSEMBLY

Fang Hanyan 1 , Lu Jiong 1,*

1 Department of Chemistry, National University of Singapore, 117543 Singapore Email: hanyan.f@nus.edu.sg

Patterning antidots ("voids") into well-defined antidot lattices creates an intriguing class of artificial structures for the periodic modulation of 2D electron systems[1], leading to anomalous transport properties and exotic quantum phenomena as well as enabling the precise bandgap engineering of 2D materials to address technological bottleneck issues. However, realizing such atomic-scale quantum antidots (QADs) is infeasible by current nanolithographic techniques. Here, we report an atomically-precise bottom-up fabrication of a series of atomic-scale QADs with elegantly engineered quantum states through a controllable assembly of a chalcogenide single vacancy (SV) in 2D PtTe 2 , a type-II Dirac semimetal. Te SVs as atomic-scale "antidots" undergo thermal migration and assembly into highly-ordered SV lattices spaced by a single Te atom, reaching the ultimate downscaling limit of antidot lattices. Increasing the number of SVs in QADs strengthens the cumulative repulsive potential and consequently enhances collective interference of multiple-pocket scattered quasiparticles inside QADs, creating multi-level quantum hole states with tunable gap from telecom to far-infrared regime. Moreover, precisely engineered quantum hole states of QADs are symmetry-protected and thus survive upon atom-by-atom oxygen substitutional doping. Therefore, SV-assembled QADs exhibit unprecedented robustness and property tunability, which not only holds the key to their future applications but also embody a wide variety of material technologies.

Fig. Atomically-precise QADs assembled by a single Te vacancy superlattice on PtTe2 surface. (a-d), Atomic structure (e-h), Constant height STM images and (i-l), nc-AFM images of geometrically well-defined triangular QADs ranging from trimer to hexamer to decamer to pentadecamer.

References [1] B. S. Jessen et al., Nature Nanotechnology 14, 340 (2019).

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