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arXiv · 2501.09715

Large moir\'{e} superstructure of stacked incommensurate charge density waves

B. Q. Lv·Yifan Su·Alfred Zong·Qiaomei Liu·Dong Wu·Noah F. Q. Yuan·Zhengwei Nie·Jiarui Li·Suchismita Sarker·Sheng Meng·Jacob P. C. Ruff·N. L. Wang·Nuh Gedik
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Abstract

Recent advances in van der Waals heterostructures have opened the new frontier of moir\'{e} physics, whereby tuning the interlayer twist angle or adjusting lattice parameter mismatch have led to a plethora of exotic phenomena such as unconventional superconductivity and fractional quantum spin Hall effect. We extend the concept of moir\'{e} engineering to materials that host incommensurate orders, where we discovered a long-period, thermally-hysteretic moir\'{e} superlattice in a layered charge density wave (CDW) compound, EuTe$_\text{4}$. Using high-momentum-resolution X-ray diffraction performed on ultrathin flakes, we found two coexisting, incommensurate CDWs with slightly mismatched in-plane wavevectors. The interaction between these two CDWs leads to their joint commensuration with the high-symmetry lattice as well as a large moir\'{e} superstructure with an in-plane period of 13.6~nm. Due to different out-of-plane orders of the incommensurate CDWs, the moir\'{e} superstructure exhibits a clear thermal hysteresis, accounting for the large hysteresis observed in electrical resistivity and numerous metastable states induced by light or electrical pulses. Our findings pave the way for a new development in moir\'{e} engineering based on an incommensurate lattice. They further highlight the important role of interlayer ordering in determining the macroscopic properties of these stacked incommensurate structures.

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B. Q. Lv, Yifan Su, Alfred Zong, Qiaomei Liu, Dong Wu, Noah F. Q. Yuan, Zhengwei Nie, Jiarui Li, Suchismita Sarker, Sheng Meng, Jacob P. C. Ruff, N. L. Wang, Nuh Gedik. 2025-01-16. Large moir\'{e} superstructure of stacked incommensurate charge density waves. https://doi.org/10.1038/s41563-025-02360-1

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