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arXiv · 2310.20373

Chiral charge density wave and backscattering-immune orbital texture in monolayer 1T-TiTe2

Mingqiang Ren·Fangjun Cheng·Yufei Zhao·Mingqiang Gu·Qiangjun Cheng·Binghai Yan·Qihang Liu·Xucun Ma·Qikun Xue·Can-Li Song
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Abstract

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.

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Mingqiang Ren, Fangjun Cheng, Yufei Zhao, Mingqiang Gu, Qiangjun Cheng, Binghai Yan, Qihang Liu, Xucun Ma, Qikun Xue, Can-Li Song. 2023-10-31. Chiral charge density wave and backscattering-immune orbital texture in monolayer 1T-TiTe2. https://doi.org/10.1021/acs.nanolett.3c03692

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