2014/07/26 by Hui‐Fei Zhai, Hui-Fei Zhai, Zhang‐Tu Tang +25 · 122 citations
Materials Science · Mathematics · Physics and Astronomy · #Condensed matter physics #Iron-based superconductors research #Mathematics #Organic and Molecular Conductors Research #Physics #Quantum mechanics #Rare-earth and actinide compounds #Superconductivity #Valence (chemistry) #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.90.064518
published in Physical Review B 90(6) (American Physical Society) · 10 pages, 6 figures
arxiv created 2014/07/26 · openalex publication_date 2014/08/29 · arxiv updated 2014/09/10 · openalex created_date 2016/10/14 · openalex updated_date 2026/08/05
Superconductivity (SC) and charge-density wave (CDW) are two contrasting yet relevant collective electronic states, which have received sustained interest for decades. Here, we report that, in a layered europium bismuth sulfofluoride, EuBiS2F, a CDW-like transition occurs at 280 K, below which SC emerges at 0.3 K, without any extrinsic doping. The Eu ions were found to exhibit an anomalously temperature-independent mixed valence of about +2.2, associated with the formation of a possible dynamic CDW. The mixed valence of Eu gives rise to self electron doping into the conduction bands mainly consisting of the in-plane Bi6p states, which in turn brings about the CDW and SC. In particular, the electronic specific-heat coefficient is enhanced by \ensuremath∼50 times, owing to the significant hybridizations between Eu4f and Bi6p electrons, as verified by band-structure calculations. Thus EuBiS2F manifests itself as an unprecedented material that simultaneously accommodates SC, CDW, and f-electron valence instability.