Moiré metrology of energy landscapes in van der Waals heterostructures

Nature (submitted), (2020)

Moiré metrology of energy landscapes in van der Waals heterostructures

Dorri Halbertal,Nathan R. Finney,Sai S. Sunku,Alexander Kerelsky,Carmen Rubio-Verdú,Sara Shabani,Lede Xian,Stephen Carr,Shaowen Chen,Charles Zhang,Lei Wang,Derick Gonzalez-Acevedo, Alexander S. McLeod,Daniel Rhodes,Kenji Watanabe,Takashi Taniguchi,Efthimios Kaxiras,Cory R. Dean,James C. Hone,Abhay N. Pasupathy,Dante M. Kennes,Angel Rubio,D. N. Basov

The emerging field of twistronics, which harnesses the twist angle between layers of two-dimensional materials, has revolutionized quantum materials research1,2. The twist between the layers creates a moiré superlattice, a large-scale periodic modulation, with dramatic impact on properties of two-dimensional systems. This approach offers the novel means to control topology and strong correlations – topics of great interest in contemporary quantum physics1–33. At the small twist limit, and particularly under strain, as atomic relaxation becomes prevalent the emergent moiré superlattice encodes elusive insights into the local interaction between the layers. Here we introduce moiré metrology as an experiment-theory codesign framework to probe the stacking energy landscape of bilayer structures at the 0.1 meV/atom scale, outperforming the gold-standard of quantum chemistry34,35. We study the shapes of moiré domains and their boundaries, as visualized with numerous nano-imaging techniques. We compare these experimental maps with real-space atomic relaxation simulations, and through this process assess and refine models for the interlayer interaction. We document the prowess of moiré metrology for three representative systems: twisted bilayer graphene, twisted double bilayer graphene and twisted H-stacked MoSe2/WSe2. Moiré metrology establishes sought after experimental benchmarks36 for binding and exfoliation energies and improves account of the stacking energy function, thus enabling accurate modelling of twisted multilayers.

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arxiv
http://arxiv.org/abs/2008.04835.pdf

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