We present results of ab-initio calculations of the electronic band structure, lattice dynamical properties, and elastic constants of LaOFeAs, the parent compound of the recently discovered superconducting iron-oxypnictide (LaO1-xFxFeAs). The total and partial electronic density of states (EDOS) of the undoped LaOFeAs (in the insulating or metallic state) are extracted from the electronic band structure. The phonon dispersion and the phonon density of states (PDOS) are also studied. Possible implications of the band structure, EDOS, and PDOS of LaOFeAs on the eventual appearance of high-Tc superconductivity upon carrier doping are discussed. The values of various independent elastic constants for both insulating and metallic states are estimated and discussed.
Elastic properties of ternary arsenide SrFe2As2 and quaternary oxyarsenide LaOFeAs as basic phases for new 38-55K superconductors from first principles
Frustrated Magnetic Interactions, Giant Magneto-Elastic Coupling, and Magnetic Phonons in Iron-Pnictides
我们提出了一个详细的第一性原理研究的Fe-磷族化合物，特别强调竞争磁相互作用，结构相变，巨磁弹性耦合及其对声子的影响。对于LaOFeAs，交换相互作用$J_{i,j}(R)$的计算结果为$\approx 12 $ = $. We find that $ J_{i,j}（R）$ has an oscillatory character with an envelop decaying as $ 1/R^3 $ along the stripe-direction while it is very short range along the diagonal direction and antiferromagnetic. A brief discussion of the neutron scattering determination of these exchange constants from a single crystal sample with orthorhombic twinning is given. The lattice parameter dependence of the exchange constants, $ dJ_{i,j} /da $ are calculated for a simple spin-Peierls like model to e…
Anomalous magneto-elastic coupling in Au-doped BaFe2As2
我们使用偏振分辨拉曼散射研究Ba（Fe $_{1-x}$ Au $_{x}$）$_2$作为轻Au掺杂的函数的$_2$晶体中的磁弹性耦合，材料的结构转变温度（$T_S$）和磁有序转变温度（$T_N$）分裂。我们研究的外观的$A_g$（As）的声子强度的$XY$散射几何形状是非常弱的$T_S$，但其强度显着增强低于$T_N$。此外，$A_g$（As）声子在$T_N$以下表现出不对称的线型，并且在磁相中Au掺杂时表现出异常的线宽展宽。我们证明了$XY$散射几何中$A_g$（As）声子模的反常行为可以用Fano模型一致地描述，该模型涉及$A_g$（As）声子模与$B_{2g}$类磁连续体相互作用，其中磁弹性耦合常数与磁序参量成正比.
Microscopic origin of the nemato-elastic coupling and dynamics of hybridized collective nematic-phonon excitations
Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Carl Zeiss SMT GmbH（卡尔蔡司SMT有限公司）；Ariel University（阿里埃勒大学）；University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
Magneto-elastic coupling between copper spin configurations and oxygen octahedra in La(2-x)Sr(x)CuO(4). Untwinning, Raman (phonon) spectrum, and neutron response
