We investigate the Ti-doping effect on the charge density wave (CDW) of 1T-TaS2 by combining scanning tunneling microscopy (STM) measurements and first-principle calculations. Although the Ti-doping induced phase evolution seems regular with increasing of the doping concentration (x), an unexpected chiral CDW phase is observed in the sample with x = 0.08, in which Ti atoms almost fully occupy the central Ta atoms in the CDW clusters. The emergence of the chiral CDW is proposed to be from the doping-enhanced orbital order. Only when x = 0.08, the possible long-range orbital order can trigger the chiral CDW phase. Compared with other 3d-elements doped 1T-TaS2, the Ti-doping retains the electronic flat band and the corresponding CDW phase, which is a prerequisite for the emergence of chirality. We expect that introducing elements with a strong orbital character may induce a chiral charge order in a broad class of CDW systems. The present results open up another avenue for further exploring the chiral CDW materials.
@article{arxiv.2105.09589,
title = {Chiral charge density waves induced by Ti-doping in 1T-TaS2},
author = {J. J. Gao and W. H. Zhang and J. G. Si and X. Luo and J. Yan and Z. Z. Jiang and W. Wang and H. Y. Lv and P. Tong and W. H. Song and X. B. Zhu and W. J. Lu and Y. Yin and Y. P. Sun},
journal= {arXiv preprint arXiv:2105.09589},
year = {2021}
}