论文标题
磁铁矿中的trimeron-phonon耦合
Trimeron-phonon coupling in magnetite
论文作者
论文摘要
使用密度函数理论，我们研究了高温立方和低温单斜层阶段的磁铁矿（Fe $ _3 $ o $ _4 $）的晶格动力学特性。将计算出的声子分散曲线和状态的声子密度与无弹性中子，非弹性X射线和核非弹性散射获得的可用实验数据进行了比较。我们发现单智性$ cc $结构的理论和实验结果之间的一致性非常好，揭示了电荷轨道（Trimeron）订单与特定声子模式之间的强耦合。对于立方阶段，出现明显的差异，可以明显地理解，假设强大的Trimeron-Phonon耦合可以扩展到Verwey过渡的上方，并且受晶格动力学受到短距离Trimeron Order的影响，而不是平均立方体结构。我们的结果确定了Trimerons（和Trimeron-Phonon耦合）在解释磁铁矿的物理学的有效性，这是其原始配方的范围。
Using density functional theory, we study the lattice dynamical properties of magnetite (Fe$_3$O$_4$) in the high-temperature cubic and low-temperature monoclinic phases. The calculated phonon dispersion curves and phonon density of states are compared with the available experimental data obtained by inelastic neutron, inelastic x-ray, and nuclear inelastic scattering. We find a very good agreement between the theoretical and experimental results for the monoclinic $Cc$ structure revealing the strong coupling between charge-orbital (trimeron) order and specific phonon modes. For the cubic phase, clear discrepancies arise which, remarkably, can be understood assuming that the strong trimeron-phonon coupling can be extended above the Verwey transition, with lattice dynamics influenced by the short-range trimeron order instead of the average cubic structure. Our results establish the validity of trimerons (and trimeron-phonon coupling) in explaining the physics of magnetite much beyond their original formulation.
