Measurement of the dynamic charge susceptibility near the charge density wave transition in ErTe3

• 成果类型: Article
• 署名作者: Chaudhuri, Dipanjan; Jiang, Qianni; Guo, Xuefei; Chen, Jin; Kengle, Caitlin S.; Hoveyda-Marashi, Farzaneh; Bernal-Choban, Camille; de Vries, Niels; Chiang, Tai-Chang; Fradkin, Eduardo; Fisher, Ian R.; Abbamonte, Peter
• 署名单位: University of Illinois System; University of Illinois Urbana-Champaign; University of Illinois System; University of Illinois Urbana-Champaign; Stanford University; University of Illinois System; University of Illinois Urbana-Champaign
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-15255
• DOI: 10.1073/pnas.2424430122
• 发表日期: 2025-06-24
• 关键词: x-ray; SCATTERING; 2h-tase2; state

摘要

A charge density wave (CDW) is a phase of matter characterized by a periodic modulation of valence electron density coupled with lattice distortion. Its formation is closely tied to the dynamical charge susceptibility, x(q, 0)), which reflects the collective electron dynamics of the material. Despite decades of study, x(q, 0)) near a CDW transition has never been measured at nonzero momentum, q, with meV energy resolution. Here, we investigate the canonical CDW transition in ErTe3 using momentum-resolved electron energy loss spectroscopy, a technique uniquely sensitive to valence band charge excitations. Unlike phonons, which soften via the Kohn anomaly, we find the electronic excitations exhibit purely relaxational dynamics well described by a diffusive model, with the diffusivity peaking just below the critical temperature, TC1. Additionally, we report for the first time a divergence in the real part of x(q, 0)) in the static limit (0)-0), a long-predicted hallmark of CDWs. Unexpectedly, this divergence occurs as T-0, with only a weak thermodynamic signature at T = TC1. Our study necessitates a reexamination of the traditional description of CDW formation in quantum materials.