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Chin. Phys. B, 2026, Vol. 35(2): 026801    DOI: 10.1088/1674-1056/ae23ac
Special Issue: SPECIAL TOPIC — Moiré physics in two-dimensional materials
SPECIAL TOPIC — Moiré physics in two-dimensional materials Prev   Next  

Three-dimensional flat bands and possible interlayer triplet pairing superconductivity in the alternating twisted NbSe2 moiré bulk

Shuang Liu(刘爽)1,2, Peng Chen(陈鹏)2,3,4, and Shihao Zhang(张世豪)1,†
1 School of Physics and Electronics, Hunan University, Changsha 410082, China;
2 Department of Physics, Guangdong Technion-Israel Institute of Technology, Shantou 515063, China;
3 Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel;
4 Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion, Guangdong Technion-Israel Institute of Technology, Shantou 515063, China
Abstract  Moiré superlattices hosting flat bands and correlated states have become a central focus in condensed matter research. Using first-principles calculations, we investigate three-dimensional flat bands in alternating twisted NbSe$_2$ moiré bulk structures, which exhibit stronger interlayer interactions than twisted bilayer configurations. Our results show that moiré bulks undergo spontaneous large-scale structural relaxation, leading to the formation of remarkably flat energy bands at twist angles $\leq 7.31^\circ$. The $k_z$-dependent dispersion of these flat bands across different moiré bulks highlights their intrinsic three-dimensional character. Moreover, the presence of out-of-plane mirror symmetry in these moiré bulk structures indicates potential interlayer triplet superconducting pairing mechanisms, distinct from those in twisted bilayer systems. This work opens new avenues for exploring three-dimensional flat bands in other moiré bulk systems.
Keywords:  moiré superlattices      first-principles calculations      electronic structure  
Received:  20 September 2025      Revised:  13 November 2025      Accepted manuscript online:  25 November 2025
PACS:  68.65.-k (Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties)  
  71.15.Mb (Density functional theory, local density approximation, gradient and other corrections)  
  73.21.Cd (Superlattices)  
  74.20.-z (Theories and models of superconducting state)  
Fund: This work was supported by the National Key Research and Development Program of China (Grant No. 2024YFA1410300), the National Natural Science Foundation of China (Grant No. 12304217), the Natural Science Foundation of Hunan Province (Grant No. 2025JJ60002), and the Fundamental Research Funds for the Central Universities of China (Grant No. 531119200247).
Corresponding Authors:  Shihao Zhang     E-mail:  zhangshh@hnu.edu.cn

Cite this article: 

Shuang Liu(刘爽), Peng Chen(陈鹏), and Shihao Zhang(张世豪) Three-dimensional flat bands and possible interlayer triplet pairing superconductivity in the alternating twisted NbSe2 moiré bulk 2026 Chin. Phys. B 35 026801

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