Many-body instabilities and topological physics are two attractive topics in condensed matter physics. It is intriguing to explore the interplay between these phenomena in a single quantum material. Here, using the prototypical charge density wave (CDW) material monolayer 1H-NbSe2 as an example, we show how momentum-dependent electron-phonon coupling drives the CDW transition from 3×3 to 2×2 phase under electron doping. More interestingly, we find the coexistence of superconductivity and nontrivial topology in one of the two 2×2 CDW phases, the latter of which is identified by the nonzero Z2 invariant with ideal Dirac cone edge states near the Fermi level. A similar CDW transition-induced topological superconductor has also been confirmed in monolayer 1H-TaSe2. Our findings not only reveal a unique and general method to introduce nontrivial topology by CDW transition, but also provide an ideal platform to modulate different quantum orders by electron doping, thus stimulating experimental interest.
@article{arxiv.2210.07633,
title = {Emergent Topological Superconductor by Charge Density Wave Transition},
author = {Zishen Wang and Jingyang You and Chuan Chen and Jinchao Mo and Jingyu He and Lishu Zhang and Jun Zhou and Kian Ping Loh and Yuan Ping Feng},
journal= {arXiv preprint arXiv:2210.07633},
year = {2022}
}