Modified magnetism within the coherence volume of superconducting Fe1 delta SexTe1-x

作者：Leiner, J^*; Thampy, V; Christianson, A D; Abernathy, D L; Stone, M B; Lumsden, M D; Sefat, A S; Sales, B C; Hu, Jin; Mao, Zhiqiang; Bao, Wei; Broholm, C

来源：Physical Review B, 2014, 90(10): 100501.

DOI：10.1103/PhysRevB.90.100501

• HIGH-TEMPERATURE SUPERCONDUCTIVITY
• SPIN EXCITATIONS
• PAIRING MECHANISM
• CONDENSATION
• RESONANCE
• ENERGY

Neutron scattering is used to probe magnetic interactions as superconductivity develops in optimally doped Fe1 delta SexTe1-x. Applying the first moment sum rule to comprehensive neutron scattering data, we extract the change in magnetic exchange energy Delta[J(R-R')< S-R . S-R'>] in the superconducting state referenced to the normal state. Oscillatory changes are observed for Fe-Fe displacements |Delta R| < xi where xi = 1.3(1) nm is the superconducting coherence length. Dominated by a large reduction in the second nearest neighbor exchange energy [-1.2(2) meV/Fe], the overall reduction in magnetic interaction energy is Delta < H-mag > = -0.31(9) meV/Fe. Comparison to the superconducting condensation energy Delta E-SC = -0.013(1) meV/Fe, which we extract from specific heat data, suggests the modified magnetism we probe drives superconductivity in Fe1 delta SexTe1-x.

• 出版日期2014-9-2
• 单位中国人民大学