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arXiv 1108.5698cond-mat.supr-concond-mat.str-el
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超导Rb2Fe4Se5的光学电导

Optical conductivity of superconducting Rb2Fe4Se5

A. Charnukha, J. Deisenhofer, D. Pröpper, M. Schmidt, Z. Wang, Y. Goncharov, A. N. Yaresko, V. Tsurkan, B. Keimer, A. Loidl, A. V. Boris

摘要:

本文报道了用宽带椭圆偏振光谱和时域透射光谱法在4 K<=T<=300 K,1 meV<= $\hbar$ ω<=6.5 eV的光谱范围内测量了高质量近化学计量比的Rb_2Fe_4Se_5(RFS)单晶(Tc=32 K)的复介电函数。该化合物同时显示超导和半导体光学响应。它揭示了由一组自旋控制的带间跃迁确定的0.45 eV的直接带隙。在100 K以下,我们在最低THz光谱范围内观察到明显的金属响应,其特征在于负介电常数ε1和裸(未屏蔽)ωpl=100 meV。在超导转变时,这种金属响应表现出低于8 meV的超导能隙的特征。我们的研究结果表明,超导性和磁性共存,在这种化合物作为两个单独的阶段。

英文摘要:

We report the complex dielectric function of high-quality nearly-stoichiometric Rb2Fe4Se5 (RFS) single crystals with Tc=32 K determined by wide-band spectroscopic ellipsometry and time-domain transmission spectroscopy in the spectral range 1 meV<=$\hbar$ω<=6.5 eV at temperatures 4 K<=T<=300 K. This compound simultaneously displays a superconducting and a semiconducting optical response. It reveals a direct band-gap of 0.45 eV determined by a set of spin-controlled interband transitions. Below 100 K we observe in the lowest THz spectral range a clear metallic response characterized by the negative dielectric permittivity ε1 and bare (unscreened) ωpl=100 meV. At the superconducting transition this metallic response exhibits a signature of a superconducting gap below 8 meV. Our findings suggest a coexistence of superconductivity and magnetism in this compound as two separate phases.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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