School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Phys Rev Lett. 2018 Aug 3;121(5):057001. doi: 10.1103/PhysRevLett.121.057001.
Recent experiments in iron pnictide superconductors reveal that, as the putative magnetic quantum critical point is approached, different types of magnetic order coexist over a narrow region of the phase diagram. Although these magnetic configurations share the same wave vectors, they break distinct symmetries of the lattice. Importantly, the highest superconducting transition temperature takes place close to this proliferation of near-degenerate magnetic states. In this Letter, we employ a renormalization group calculation to show that such a behavior naturally arises due to the effects of spin-orbit coupling on the quantum magnetic fluctuations. Formally, the enhanced magnetic degeneracy near the quantum critical point is manifested as a stable Gaussian fixed point with a large basin of attraction. Implications of our findings to the superconductivity of the iron pnictides are also discussed.
最近在铁磷族高温超导体中的实验表明，随着假设的磁量子临界点的接近，不同类型的磁有序在相图的一个狭窄区域内共存。虽然这些磁性组态共享相同的波矢，但它们打破了晶格的不同对称。重要的是，最高的超导转变温度发生在这些近简并磁态增殖的附近。在这封信中，我们采用重整化群计算表明，由于自旋轨道耦合对量子磁涨落的影响，这种行为是自然出现的。形式上，在量子临界点附近增强的磁性简并性表现为具有大吸引域的稳定高斯不动点。我们的发现对铁磷族高温超导体的超导性的影响也进行了讨论。
