Observation of a critical charge mode in a strange metal

• 成果类型: Article
• 署名作者: Kobayashi, Hisao; Sakaguchi, Yui; Kitagawa, Hayato; Oura, Momoko; Ikeda, Shugo; Kuga, Kentaro; Suzuki, Shintaro; Nakatsuji, Satoru; Masuda, Ryo; Kobayashi, Yasuhiro; Seto, Makoto; Yoda, Yoshitaka; Tamasaku, Kenji; Komijani, Yashar; Chandra, Premala; Coleman, Piers
• 署名单位: RIKEN; University of Tokyo; University of Tokyo; University of Tokyo; Johns Hopkins University; Johns Hopkins University; Kyoto University; Hirosaki University; Japan Synchrotron Radiation Research Institute; University System of Ohio; University of Cincinnati; Rutgers University System; Rutgers University New Brunswick; University of London; Royal Holloway University London
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8852
• DOI: 10.1126/science.abc4787
• 发表日期: 2023-03-03
• 页码: 908-911
• 关键词: quantum criticality; mixed-valence; fermi-surface; intermediate-valence; stochastic-theory; mossbauer; resonance; fluctuations; electron; exchange

摘要

Understanding the strange metallic behavior that develops at the brink of localization in quantum materials requires probing the underlying electronic charge dynamics. Using synchrotron radiation-based Mossbauer spectroscopy, we studied the charge fluctuations of the strange metal phase of beta-YbAlB4 as a function of temperature and pressure. We found that the usual single absorption peak in the Fermi-liquid regime splits into two peaks upon entering the critical regime. We interpret this spectrum as a single nuclear transition, modulated by nearby electronic valence fluctuations whose long time scales are further enhanced by the formation of charged polarons. These critical charge fluctuations may prove to be a distinct signature of strange metals.