Superconductivity from orbital nematic fluctuations
Superconductivity from orbital nematic fluctuations
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DOI：
10.1103/physrevb.88.180502
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发表时间：
2013-03
影响因子：
3.7
通讯作者：
H. Yamase;R. Zeyher
中科院分区：
文献类型：
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作者：
H. Yamase;R. Zeyher
最近的实验表明，除了反铁磁涨落之外，向列涨落可能有助于铁磷族元素中超导性的发生。受这一观察的启发，我们研究了最小二能带模型中向列涨落的超导性。所采用的能带参数适用于铁磷族化物，并导致费米线的四个口袋。结果表明，口袋内的低能量、长波长向列涨落会产生强耦合超导性，而口袋之间的大动量密度涨落则无关紧要。获得的转变温度与通常在磷族元素中发现的转变温度相似，并且对于排斥库仑相互作用相当稳健。超导态和向列态共存于相图的大范围内。
Recent experiments suggest that, besides antiferromagnetic fluctuations, nematic fluctuations may contribute to the occurrence of superconductivity in iron pnictides. Motivated by this observation, we study superconductivity from nematic fluctuations in a minimal two-band model. The employed band parameters are appropriate for iron pnictides and lead to four pockets for the Fermi line. It is shown that low-energy, long-wavelength nematic fluctuations within the pockets give rise to strong-coupling superconductivity whereas the large momenta density fluctuations between pockets are rather irrelevant. The obtained transition temperatures are similar to those typically found in the pnictides and are rather robust against repulsive Coulomb interactions. The superconducting and nematic states coexist in a large region of the phase diagram.