Unconventional Hysteretic Transition in a Charge Density Wave

• Published in: Physical review letters 2022-01, Vol.128 (3), p.036401-036401, Article 036401
• Main Authors: Lv, B Q, Zong, Alfred, Wu, D, Rozhkov, A V, Fine, Boris V, Chen, Su-Di, Hashimoto, Makoto, Lu, Dong-Hui, Li, M, Huang, Y-B, Ruff, Jacob P C, Walko, Donald A, Chen, Z H, Hwang, Inhui, Su, Yifan, Shen, Xiaozhe, Wang, Xirui, Han, Fei, Po, Hoi Chun, Wang, Yao, Jarillo-Herrero, Pablo, Wang, Xijie, Zhou, Hua, Sun, Cheng-Jun, Wen, Haidan, Shen, Zhi-Xun, Wang, N L, Gedik, Nuh
• Format: Article
• Language: English
• Subjects: Angle-resolved photoemission spectroscopy; Charge density waves; Electron diffraction; Electronic structure; Phase transitions; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Resistivity measurements; Transport phenomena; X-ray absorption spectroscopy; X-ray diffraction
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.128.036401

Hysteresis underlies a large number of phase transitions in solids, giving rise to exotic metastable states that are otherwise inaccessible. Here, we report an unconventional hysteretic transition in a quasi-2D material, EuTe_{4}. By combining transport, photoemission, diffraction, and x-ray absorption measurements, we observe that the hysteresis loop has a temperature width of more than 400 K, setting a record among crystalline solids. The transition has an origin distinct from known mechanisms, lying entirely within the incommensurate charge density wave (CDW) phase of EuTe_{4} with no change in the CDW modulation periodicity. We interpret the hysteresis as an unusual switching of the relative CDW phases in different layers, a phenomenon unique to quasi-2D compounds that is not present in either purely 2D or strongly coupled 3D systems. Our findings challenge the established theories on metastable states in density wave systems, pushing the boundary of understanding hysteretic transitions in a broken-symmetry state.