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arXiv · 2406.16709

Evidence of directional structural superlubricity and L\'evy flights in a van der Waals heterostructure

Maxime Le Ster·Paweł Krukowski·Maciej Rogala·Paweł Dabrowski·Iaroslav Lutsyk·Klaudia Toczek·Krzysztof Podlaski·Tefvik O. Mendeş·Francesca Genuzio·Andrea Locatelli·Guan Bian·Tai-Chang Chiang·Simon A. Brown·Paweł J. Kowalczyk
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Abstract

Structural superlubricity is a special frictionless contact in which two crystals are in incommensurate arrangement such that relative in-plane translation is associated with vanishing energy barrier crossing. So far, it has been realized in multilayer graphene and other van der Waals two-dimensional crystals with hexagonal or triangular crystalline symmetries, leading to isotropic frictionless contacts. Directional structural superlubricity, to date unrealized in two-dimensional systems, is possible when the reciprocal lattices of the two crystals coincide in one direction only. Here, we evidence directional structural superlubricity a $\alpha$-bismuthene/graphite van der Waals system, manifested by spontaneous hopping of the islands over hundreds of nanometres at room temperature, resolved by low-energy electron microscopy and supported by registry simulations. Statistical analysis of individual and collective $\alpha$-bismuthene islands populations reveal a heavy-tailed distribution of the hopping lengths and sticking times indicative of L{\'e}vy flight dynamics, largely unobserved in condensed-matter systems.

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Maxime Le Ster, Paweł Krukowski, Maciej Rogala, Paweł Dabrowski, Iaroslav Lutsyk, Klaudia Toczek, Krzysztof Podlaski, Tefvik O. Mendeş, Francesca Genuzio, Andrea Locatelli, Guan Bian, Tai-Chang Chiang, Simon A. Brown, Paweł J. Kowalczyk. 2024-06-24. Evidence of directional structural superlubricity and L\'evy flights in a van der Waals heterostructure. https://doi.org/10.1002/smll.202408349

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