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arXiv · 0905.3559

Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6

Yiming Qiu·Wei Bao·Yang Zhao·Collin Broholm·V. Stanev·Z. Tesanovic·Y. C. Gasparovic·S. Chang·Jin Hu·Bin Qian·Minghu Fang·Zhiqiang Mao
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Abstract

Neutron scattering is used to probe magnetic excitations in FeSe_{0.4}Te_{0.6} (T_c=14 K). Low energy spin fluctuations are found with a characteristic wave vector $(0.5,0.5,L)$ that corresponds to Fermi surface nesting and differs from Q_m=(δ,0,0.5) for magnetic ordering in Fe_{1+y}Te. A spin resonance with \hbarΩ_0=6.5 meV \approx 5.3 k_BT_c and \hbarΓ=1.25 meV develops in the superconducting state from a normal state continuum. We show that the resonance is consistent with a bound state associated with s+/- superconductivity and imperfect quasi-2D Fermi surface nesting.

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Yiming Qiu, Wei Bao, Yang Zhao, Collin Broholm, V. Stanev, Z. Tesanovic, Y. C. Gasparovic, S. Chang, Jin Hu, Bin Qian, Minghu Fang, Zhiqiang Mao. 2009-05-21. Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6. https://doi.org/10.1103/physrevlett.103.067008

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