On the kagome lattice, electrons benefit from the simultaneous presence of band topology, flat electronic bands, and van Hove singularities, forming competing or cooperating orders. Understanding the interrelation between these distinct order parameters remains a significant challenge, leaving much of the associated physics unexplored. In the kagome superconductor KV3Sb5, which exhibits a charge density wave (CDW) state below T = 78 K, we uncover an unpredicted field-induced phase transition below 6 K. The observed transition is marked by a hysteretic anomaly in the resistivity, nonlinear electrical transport, and a change in the symmetry of the electronic response as probed via the angular dependence of the magnetoresistivity. These observations surprisingly suggest the emergence of an unanticipated broken symmetry state coexisting with the original CDW. To understand this experimental observation, we developed a theoretical minimal model for the normal state inside the high-temperature parent CDW phase where an incommensurate CDW order emerges as an instability sub-leading to superconductivity. The incommensurate CDW emerges when superconducting fluctuations become fully suppressed by large magnetic fields. Our results suggest that, in kagome superconductors, quantum states can either coexist or are nearly degenerate in energy, indicating that these are rich platforms to expose new correlated phenomena.
@article{arxiv.2501.13260,
title = {Field induced density wave in a kagome superconductor},
author = {Md Shafayat Hossain and Qi Zhang and Julian Ingham and Jinjin Liu and Sen Shao and Yangmu Li and Yuxin Wang and Bal K. Pokharel and Zi-Jia Cheng and Yu-Xiao Jiang and Maksim Litskevich and Byunghoon Kim and Xian Yang and Yongkai Li and Tyler A. Cochran and Yugui Yao and Dragana Popović and Zhiwei Wang and Guoqing Chang and Ronny Thomale and Luis Balicas and M. Zahid Hasan},
journal= {arXiv preprint arXiv:2501.13260},
year = {2025}
}