2021/06/17 by B. Q. Lv, Alfred Zong, D. Wu +25 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.128.036401
published as Phys. Rev. Lett. 128, 036401 (2022)
arxiv created 2021/06/17 · arxiv updated 2022/02/01
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, EuTe4. By combining transport, photoemission, diffraction, and x-ray absorption measurements, we observed 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 EuTe4 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.