We have studied the momentum dependence of the energy gap of Bi 2(Sr,R)2CuOy by angle-resolved photoemission spectroscopy (ARPES), particularly focusing on the difference between R=La and Eu. By comparing the gap function and characteristic temperatures between the two sets of samples, we show that there exist three distinct energy scales, Δpg, Δsc0, and Δsc0eff, which correspond to T* (pseudogap temperature), Tonset (onset temperature of fluctuating superconductivity), and Tc (critical temperature of coherent superconductivity). The results not only support the existence of a pseudogap state below T* that competes with superconductivity, but also the duality of competition and superconducting fluctuation at momenta around the antinode below Tonset.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2011 3 10|
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