AI 中文总结
研究双层1T-TaSe₂两种堆叠几何结构，利用多种手段发现其实现准一维相互作用链，不同堆叠机制不同，A-C′堆叠有面外铁电极化，还能通过外场切换构型，证明其是相互作用驱动电子铁电性平台，建立相关态家族。
AI 中文摘要
窄带系统中的强电子关联为实现新兴量子相提供了一条有前景的途径。虽然范德华材料中的铁电性通常与晶格畸变、层间滑动或莫尔重构驱动的反演对称性破缺有关，但直接从电子相互作用产生铁电性的可能性在很大程度上仍未得到探索。本文利用分子束外延、扫描隧道显微镜和从头算计算，研究了由耦合的大卫之星电荷密度波相形成的双层1T-TaSe₂的两种堆叠几何结构A-C和A-C′。结果表明，两种堆叠都实现了准一维相互作用链，但受不同的相互作用机制支配。A-C堆叠中，强层间杂化导致二聚化和带绝缘态的形成；而A-C′堆叠则由层间库仑相互作用主导，产生层间自发电荷不平衡，从而产生面外铁电极化。此外，还证明了铁电和反铁电链间构型可通过外部场稳定并电切换。结果证明双层1T-TaSe₂是相互作用驱动的电子铁电性的平台，在1T-TaSe₂多层膜中建立了一个被忽视的电荷有序相关态家族。
英文摘要
Strong electronic correlations in narrow-band systems provide a promising route to realize emergent quantum phases. While ferroelectricity in van der Waals materials is typically associated with inversion symmetry breaking driven by lattice distortions, interlayer sliding, or moiré reconstruction, the possibility of generating ferroelectricity directly from electronic interactions remains largely unexplored. Here, using molecular beam epitaxy, scanning tunneling microscopy, and ab initio calculations, we investigate two stacking geometries of bilayer 1T-TaSe$_2$, A-C and A-C$'$, formed by coupled Star-of-David charge density wave phases. We show that both stackings realize quasi-one-dimensional interacting chains, but are governed by distinct interaction mechanisms. In the A-C stacking, strong interlayer hybridization leads to dimerization and the formation of a band insulating state. In contrast, the A-C$'$ stacking is dominated by interlayer Coulomb interactions, producing a spontaneous charge imbalance between layers that gives rise to an out-of-plane ferroelectric polarization. Furthermore, we demonstrate that ferroelectric and antiferroelectric interchain configurations can be stabilized and electrically switched by an external field. Our results prove that bilayer 1T-TaSe$_2$ is a platform for interaction-driven electronic ferroelectricity, establishing an overlooked family of charge-ordered correlated states in 1T-TaSe$_2$ multilayers.
