局域态密度对铁基超导体能隙对称性的影响
Effect of Local Density of States on the Gap Symmetry in the Fe-Based Superconductors
摘要: 我们对解释新发现的铁基化合物中的超导体能隙对称性提出一个方案。这个方案是在赫伯德模型中研究反铁磁(AFM)自旋涨落调制的电子-电子耦合。我们发现在不同的费米面上超导能隙的对称性是不相同的，并且能隙节点的出现依赖准粒子的区域态密度（LDOS）。这个发现解释了ARPES和一些其他实验中的有争议的实验结果。
Abstract: We present a scenario for the gap symmetry observed in newly discovered unconventional superconduc- tivity of Fe-based layered compound .The scenario is explored in Hubbard model including electron-electron couplings mediated by antiferromagnetic(AFM) spin fluctuation . We find that the superconducting gap symmetries are different on different Fermi surfaces and the gap node emergence depends on the local density of states(LDOS) of quasi-particles .This mechanism explains the controversial experiment results oberved in the ARPES and some transport experiments .
文章引用：叶晓山, 马幸, 刘拥军. 局域态密度对铁基超导体能隙对称性的影响[J]. 现代物理, 2011, 1(1): 23-27. http://dx.doi.org/10.12677/mp.2011.11003

参考文献

[1] C. De La Cruz, Q. Huang, J. W. Lynn, et al. Magnetic order versus super-conductivity in the iron-based layered La(O1-xFx)FeAs systems. Nature, 2008, 453(7197): 899-902.
[2] H. H. Wen, G. Mu, L. Fang, et al. Superconductivity at 25 K in hole doped $(La_{1-x}Sr_x)OFeAs$. Europhys. Lett, 2008, 82(1): 17009-17013.
[3] J. Zhao, Q. Huang, C. De La Cruz, et al. Structural and magnetic phase diagram of Ce-FeAsO1–xFx and its relationship to high-temperature superconductivity. Nature Materials, 2008, 7(12): 953-959 .
[4] Q. Huang, Y. Qiu, W. Bao, et al. Neutron-diffraction measurements of magnetic order and a structural transition in the parent BaFe2As2 compound of FeAs-based high-temperature superconductors. Phys. Rev. Lett, 2008, 101(25): Arti-cle ID 257003.
[5] G. Li, W. Z. Hu, J. Dong, et al. Probing the super-conducting energy gap from infrared spectroscopy on a Ba0.6K0.4Fe2As2 single crystal with Tc = 37 K. Phys. Rev. Lett., 2008, 101(10): Article ID 107004.
[6] T. Y. Chen, Z. Tesanovic, R. H. Liu, et al. Determination of supercon-ducting gap of SmFeAsFxO1–x superconductors by andreev reflection spectroscopy. Nature, 2008, 453(9-12): 1224-1227.
[7] O. Millo, I. Asulin, O. Yuli, et al. Scanning tunneling spectroscopy of SmFeAsO0.85: Possible evidence for d-wave order-parameter symmetry. Phys. Rev. B, 2008, 78(9): Article ID 092505.
[8] G. Mu, X. Zhu, L. Fang, et al. Nodal gap in Fe-based layered superconductor LaO_0.9F_{0.1-delta}FeAs probed by specific heat measurements. Chin. Phys. Lett., 2008, 25(6): 2221-2224.
[9] T. Kondo, A. F. Santander-Syro, O. Copie, et al. Momentum dependence of the super-conducting gap in NdFeAsO0.9F0.1 single crystals measured by angle resolved photoemission spectroscopy. Phys. Rev. Lett, 2008, 101(14): Article ID 147003.
[10] H. Ding, P. Richard, K. Nakayama, et al. Observation of fermi-surface–dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2. Europhys. Lett., 2008, 83(4): Article ID 47001.
[11] L. Shan, Y. l. Wang, X. Y. Zhu, et al. Point-contact spec-troscopy of iron-based layered superconductor LaO$_{0.9}$F$_ {0.1-\delta}$FeAs. Europhysics Letters, 2008, 83(5): Article ID 57004.
[12] I. I. Mazin, D. J. Singh, M. D. Johannes et al. Unconven-tional superconductivity with a sign reversal in the order parameter of LaFeAsO1-xFx. Phys. Rev. Lett., 2008, 101(5): Article ID 057003.
[13] T. A. Maier, D. J. Scalapino. Theory of neutron scattering as a probe of the superconducting gap in the iron pnictides. Phys. Rev. B, 2008, 78(2): Article ID 020514(R)
[14] X. S. Ye, J. X. Li. Asymmetric d-wave superconducting gap in orthorhombic high-Tc superconductors. Phys. Rev. B, 2007, 76(17): Article ID 174503.
[15] Z. J. Yao, J. X. Li, and Z. D. Wang. New J. spin fluctuations, interband coupling, and unconventional pairing in iron-based superconductors. New J. Phys, 2009, 11(2): Article ID 025009.
[16] D. H. Lu, M. Yi, S. K. Mo, et al. Electronic structure of the iron-based superconductor LaOFeP. Nature, 2008, 455(7209): 81-84.
[17] D. H. Lu, M. Yi, S. K. et al. ARPES studies of the electronic structure of LaOFe(P, As). Physica C, 2009, 469(9-12): 452-458.
[18] B. Zeng, G. Mu, H. Q. Luo, et al. Anisot-ropic structure of the order parameter in FeSe0.45Te0.55 revealed by angle resolved specific heat. arXiv: 1007-3597.
[19] M. E. Flatte, S. Quinlan, and D. J. Scalapino. Method for measuring the momentum-dependent relative phase of the superconducting gap of high-temperature super-conductors. Phys. Rev. B, 1993, 48(14): 10626-10629.