Enhancement of Tc by disorder in underdoped iron pnictide superconductors
Enhancement of Tc by disorder in underdoped iron pnictide superconductors
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DOI：
10.1103/physrevb.85.140512
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发表时间：
2012-04-23
影响因子：
3.7
通讯作者：
Chubukov, A. V.
中科院分区：
文献类型：
--
作者：
Fernandes, R. M.;Vavilov, M. G.;Chubukov, A. V.
我们分析了无序对铁磷属化物s（+-）超导态转变温度Tc的影响。传统的看法是，T-c应迅速减少增加带间杂质散射，但我们表明，这种行为只在过掺杂区的相图。在欠掺杂的情况下，超导性从预先存在的磁性状态出现，无序引起两种竞争效应：库珀对的破坏，这往往会降低T-c，以及对巡回磁序的抑制，这往往会使T-c上升。我们表明，对于一个广泛的参数范围内的第二个效果获胜，即，在共存状态下，Tc可以随无序度增加而增加。我们的研究结果提供了一个解释最近的几个实验结果，并提供额外的支持s（+-）配对的铁pnictides。
We analyze how disorder affects the transition temperature T-c of the s(+-) superconducting state in the iron pnictides. The conventional wisdom is that T-c should rapidly decrease with increasing inter-band nonmagnetic impurity scattering, but we show that this behavior holds only in the overdoped region of the phase diagram. In the underdoped regime, where superconductivity emerges from a pre-existing magnetic state, disorder gives rise to two competing effects: breaking of the Cooper pairs, which tends to reduce T-c, and suppression of the itinerant magnetic order, which tends to bring T-c up. We show that for a wide range of parameters the second effect wins; i.e., in the coexistence state T-c can increase with disorder. Our results provide an explanation for several recent experimental findings and lend additional support to s(+-) pairing in the iron pnictides.