Band structure reconstruction across nematic order in high quality FeSe single crystal as revealed by optical spectroscopy study

• Published in: Science bulletin (Beijing) Vol. 61; no. 14; pp. 1126 - 1131
• Main Authors: Wang, Haipeng, Ye, Zirong, Zhang, Yan, Wang, Nanlin
• Format: Journal Article
• Language: English
• Published: Beijing Elsevier B.V 01.07.2016; Science China Press
• Subjects: Band reconstruction; Chemistry/Food Science; crystals; Earth Sciences; energy; Engineering; Humanities and Social Sciences; Iron-based superconductor; Life Sciences; multidisciplinary; Nematic phase; Optical spectroscopy; Physics; Science; Science (multidisciplinary); spectroscopy; vapors; 光学光谱; 光谱测量; 关联效应; 单晶生长; 等离子体频率; 结构重建; 能带; 质量; Band reconstruction; Optical spectroscopy; Nematic phase; Iron-based superconductor
• ISSN: 2095-9273; 2095-9281
• DOI: 10.1007/s11434-016-1102-2

We perform an in-plane optical spectroscopy measurement on high quality FeSe single crystals grown by a vapor transport technique. Below the structural transition at Ts - 90 K, the reflectivity spectrum clearly shows a gradual suppression around 400 cm-1 and the conductivity spectrum shows a peak at higher frequency. The energy scale of this gap-like feature is comparable to the width of the band splitting observed by ARPES. The low-frequency conductivity consists of two Drude components and the overall plasma frequency is smaller than that of the FeAs based compounds, suggesting a lower cartier density or stronger correlation effect. The plasma frequency becomes even smaller below Ts which agrees with the very small Fermi energy estimated by other experiments. Similar to iron pnictides, a clear temperature-induced spectral weight transfer is observed for FeSe, being indicative of strong correlation effect.