Emergent electronic structures from heterochiral CDW in correlated van der Waals materials

The light-induced 1T-TaS₂ hidden state, characterized by its significantly enhanced conductivity and exceptionally long lifetime, has stimulated numerous experimental and theoretical works over the past decade [1]. Despite extensive research, the mechanism and the structural origin of the insulator-to-metal transition remain elusive. The recent observation of heterochiral charge density wave (CDW) in the hidden state [2] and its connection to Nb-substituted 1T-TaS₂ [3] provide important information to this puzzle. In this talk, we will discuss the effects of doping and photodoping on the insulating CDW phase and how they lead to heterochiral CDW. Notably, the 27.8° "twist angle" between CDW domains at the heterochiral interfaces gives rise to a commensurate moiré superlattice with a Kagome tiling of all 13 CDW stackings. Our density functional theory studies of the CDW moiré superstructure reveal emergent metallicity, Kagome subsystems, and ring-shaped charge textures akin to that observed in Nb-substituted 1T-TaSe₂ [4]. Our work sheds light on novel electronic properties gained by chiral interfaces and brings intriguing prospects on light-induced moiré materials for twistronics applications.

[1] L. Stojchevska et al., Science 344, 177 (2014)

[2] W. C. Huang et al., arXiv: 2405.20872 (2024).

[3] S. Ohta et al., Phys. Rev. B 103, 155137 (2021).

[4] S. Ohta et al., Phys. Rev. B 104, 155433 (2021).