Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2009 Dec 31;103(26):267001. doi: 10.1103/PhysRevLett.103.267001. Epub 2009 Dec 22.
The puzzling nature of magnetic and lattice phase transitions of iron pnictides is investigated via a first-principles Wannier function analysis of representative parent compound LaOFeAs. A rare ferro-orbital ordering is found to give rise to the recently observed highly anisotropic magnetic coupling, and drive both phase transitions--without resorting to widely employed frustration or nesting picture. The revealed necessity of the additional orbital physics leads to a correlated electronic structure fundamentally distinct from that of the cuprates. In particular, the strong coupling to the magnons advocates active roles of light orbitons in spin dynamics and electron pairing in iron pnictides.
通过对代表性母体化合物 LaOFeAs 的第一性原理 Wannier 函数分析，研究了铁磷化物的磁有序和晶格相变的奇异性质。发现一种罕见的铁轨道有序，导致了最近观察到的高度各向异性磁耦合，并驱动了两个相变——无需诉诸于广泛应用的失谐或嵌套图。所揭示的额外轨道物理的必要性导致了与铜氧化物根本不同的关联电子结构。特别是，与磁振子的强耦合表明轻轨道子在铁磷化物的自旋动力学和电子配对中发挥着积极作用。
