Pairing instability near a lattice-influenced nematic quantum critical point
Pairing instability near a lattice-influenced nematic quantum critical point
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DOI：
10.1103/physrevb.96.195146
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发表时间：
2017-11-22
影响因子：
3.7
通讯作者：
Paul, I.
中科院分区：
文献类型：
--
作者：
Labat, D.;Paul, I.
我们研究了四方相环境中的电子系统调谐到向列相量子临界点(QCP)时超导T-c的影响。包括电子向列相变量与相应晶格应变的耦合，将临界性限制在某些高对称方向。这允许弱耦合处理，即使在QCP上也是如此。我们发展了一个判据来区分接近QCP时的弱和强的T_c增强。我们表明，只有当配对被远离QCP的非向列相互作用所主导，并且同时当电子-应变耦合足够强时，才会发生可忽略的T_c增强。我们认为这就是铁超导体的情况。
We study how superconducting T-c is affected as an electronic system in a tetragonal environment is tuned to a nematic quantum critical point (QCP). Including coupling of the electronic nematic variable to the relevant lattice strain restricts criticality only to certain high symmetry directions. This allows a weak-coupling treatment, even at the QCP. We develop a criterion distinguishing weak and strong Tc enhancements upon approaching the QCP. We show that negligible Tc enhancement occurs only if pairing is dominated by a non-nematic interaction away from the QCP, and simultaneously if the electron-strain coupling is sufficiently strong. We argue this is the case of the iron superconductors.