https://doi.org/10.1140/epjb/e2012-30315-8
Regular Article
A minimum single-band model for low-energy excitations in superconducting AxFe2−ySe2
1 College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P.R. China
2 Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
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e-mail: tzhou@nuaa.edu.cn
Received: 13 April 2012
Received in final form: 7 May 2012
Published online: 27 June 2012
We propose a phenomenological single-band model for the newly discovered iron-selenide superconductors AxFe2−ySe2 (A = Tl, K, Rb, Cs). Based on this minimum model and the random phase approximation, the dx² − y² pairing symmetry is revealed theoretically, which may be understood in the framework of Fermi surface topology. A common origin of superconductivity is elucidated for this compound and other high-Tc materials. The spin excitations at (π,π/2) in superconducting states are observed, in good agreement with the neutron scattering experiments. The spin resonance is indicated to show up only for the d-wave pairing, which provides an additional indication for the d-wave pairing symmetry in this family of superconductors.
Key words: Solid State and Materials
© The Author(s) 2012. This article is published with open access at Springerlink.com