Spontaneous symmetry breaking and emergent electronic order have been widely discussed in condensed matter physics, providing a general framework for understanding complex phase transitions in quantum materials. Layered transition-metal dichalcogenides host a particularly rich variety of charge density wave states, which often compete or coexist with superconductivity. Here, using first-principles calculations, we propose that CDW instabilities are broadly realized in 1T Janus TMD monolayers. The condensation of CDW modes removes the remaining mirror symmetry of polar Janus lattice, giving rise to a threefold polar chiral phase. Momentum-resolved electron-phonon coupling and bare Lindhard susceptibility reveal distinct microscopic characteristics across the different CDW families. These results establish Janus monolayer as a versatile playground for exploring the interplay among chirality, electronic orders, and quantum phase transitions.

冯晓龙博士,本科毕业于华中科技大学，博士毕业于新加坡科技设计大学。2023年获洪堡基金会博士后项目资助。现任德国马克斯·普朗克固体化学物理研究所拓扑量子化学研究组（Claudia Felser教授团队）理论计算方向课题组长。主要研究方向为利用有效模型与第一性原理方法，探索拓扑材料的电学、热学及磁学等物理性质。近期研究聚焦于量子材料中的声子不稳定性及其引发的电荷密度波相变行为。