Observation of pseudogaplike feature above Tc in LiFeAs by ultrafast optical spectroscopy

Kung Hsuan Lin, Kuan Jen Wang, Chung Chieh Chang, Yu Chieh Wen, Dzung Han Tsai, Yu Ruei Wu, Yao Tsung Hsieh, Ming Jye Wang, Bing Lv, Paul Ching Wu Chu, Maw Kuen Wu

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8 Citations (Scopus)


We utilize ultrafast optical spectroscopy to study the quasiparticle relaxation in stoichiometric LiFeAs crystals. According to our temperature-dependent studies, we have observed three electronic phases in LiFeAs. Below the superconducting (SC) temperature Tc (=15 K), the relaxation time of quasiparticles due to the SC gaps is far longer than 50 ps in our experimental conditions. In addition to SC gaps, we have also found a gaplike feature in the SC state. This gaplike feature is evident up to 40 K, which is above the SC temperature. The quasiparticle relaxation time due to this gaplike feature is in the range of 1-2 ps. We suggest the gaplike feature in LiFeAs is induced by magnetic fluctuations.

Original languageEnglish
Article number174502
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number17
Publication statusPublished - 2014 Nov 7

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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