Non-trivial electronic states are attracting intense attention in low-dimensional physics. Though chirality has been identified in charge states with a scalar order parameter, its intertwining with charge density waves (CDW), film thickness and the impact on the electronic behaviors remain less well understood. Here, using scanning tunneling microscopy, we report a 2 x 2 chiral CDW as well as a strong suppression of the Te-5p hole-band backscattering in monolayer 1T-TiTe2. These exotic characters vanish in bilayer TiTe2 with a non-CDW state. Theoretical calculations approve that chirality comes from a helical stacking of the triple-q CDW components and therefore can persist at the two-dimensional limit. Furthermore, the chirality renders the Te-5p bands an unconventional orbital texture that prohibits electron backscattering. Our study establishes TiTe2 as a promising playground for manipulating the chiral ground states at the monolayer limit and provides a novel path to engineer electronic properties from an orbital degree.
@article{arxiv.2310.20373,
title = {Chiral charge density wave and backscattering-immune orbital texture in monolayer 1T-TiTe2},
author = {Mingqiang Ren and Fangjun Cheng and Yufei Zhao and Mingqiang Gu and Qiangjun Cheng and Binghai Yan and Qihang Liu and Xucun Ma and Qikun Xue and Can-Li Song},
journal= {arXiv preprint arXiv:2310.20373},
year = {2023}
}