Institut Néel, CNRS/UJF, 25 avenue des Martyrs, B.P. 166, 38042 Grenoble, France.
Phys Rev Lett. 2011 Jul 22;107(4):047004. doi: 10.1103/PhysRevLett.107.047004.
We examine the relevance of magnetoelastic coupling to describe the complex magnetic and structural behavior of the different classes of the iron superconductors. We model the system as a two-dimensional metal whose magnetic excitations interact with the distortions of the underlying square lattice. Going beyond the mean field, we find that quantum fluctuation effects can explain two unusual features of these materials that have attracted considerable attention: first, why iron telluride orders magnetically at a non-nesting wave vector (π/2,π/2) and not at the nesting wave vector (π,0) as in the iron arsenides, even though the nominal band structures of both these systems are similar, and second, why the (π,0) magnetic transition in the iron arsenides is often preceded by an orthorhombic structural transition. These are robust properties of the model, independent of microscopic details, and they emphasize the importance of the magnetoelastic interaction.
我们研究了磁弹性耦合在描述不同类型铁基超导体复杂磁结构行为方面的相关性。我们将系统建模为一个二维金属，其磁激发与底层正方形晶格的畸变相互作用。超越平均场，我们发现量子涨落效应可以解释这些材料的两个引人注目的特性：首先，为什么铁碲化物在非嵌套波矢（π/2，π/2）处而不是在铁砷化物中的嵌套波矢（π，0）处有序磁，尽管这两个系统的名义能带结构相似；其次，为什么铁砷化物中的（π，0）磁转变通常先于正交结构转变。这些是模型的稳健特性，与微观细节无关，它们强调了磁弹性相互作用的重要性。
