关键词: 铁基超导体/
红外光谱/
电子关联
English Abstract
Infrared spectroscopy study of ironbased superconductor Li0.8Fe0.2 ODFeSe
Lin Tong1,Hu Die2,
Shi Li-Yu1,
Zhang Si-Jie1,
Liu Yan-Qi1,
Lv Jia-Lin1,
Dong Tao1,
Zhao Jun2,
Wang Nan-Lin1
1.International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China;
2.State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, China
Fund Project:Project supported by the National Basic Research Program of China (Grant Nos. 2016YFA0300902, 2016YFA0300203, 2017YFA0302904, 2015CB921302), the National Natural Science Foundation of China (Grant Nos. 11327806, GZ1123), and the Innovation Program of Shanghai Municipal Education Commission, China (Grant No. 2017-01-07-00-07-E00018).Received Date:22 July 2018
Accepted Date:01 August 2018
Published Online:20 October 2019
Abstract:We perform an in-plane optical spectroscopy measurement on iron-based superconductor Li0.8Fe0.2ODFeSe single crystal. At room temperature, the low frequency optical conductivity shows an incoherent characteristic; the Drude component is absent. With temperature decreasing, the Drude component develops and narrows rapidly. A well-defined plasma edge is observed in reflectance spectrum at temperature below 100 K, indicating a dramatically reduced scattering rate. The spectral weight contributed from free carriers is even smaller than that of FeSe single crystal. A number of phonon modes are visible in the measured spectra. We also observe clear spectral change below 160 cm-1 at 10 K, associated with the formation of superconducting energy gap in the superconducting state. The energy scale of the superconducting gap is comparable to the value measured by angle-resolved photoemission spectroscopy technique. Like FeSe and other iron pnictides, a clear temperature-induced spectral weight transfer at high energy is observed for Li0.8Fe0.2ODFeSe, indicating the presence of strong correlation effect.
Keywords: iron-based superconductor/
infrared spectroscopy/
electron correlation
