论文标题
通过非弹性中子散射验证第一原理声子寿命
Validating First-Principles Phonon Lifetimes via Inelastic Neutron Scattering
论文作者
论文摘要
声子寿命是转运的准颗粒理论的关键组成部分，但是第一原则的寿命很少与非弹性中子散射（INS）结果直接相比。现有的比较表明，即使在预计将是可靠的温度下，即使在温度下也存在差异。在这项工作中，我们证明了互惠空间体素（$ q $ -Voxel）是INS数据分析所需的相互空间中有限区域，必须在理论中明确考虑以进行有意义的比较。当CAF $ _2 $和$ _2 $的$ Q $ -VOXEL计算时，我们证明了散射功能的峰值宽度的准确预测。通过该测试意味着声子相互作用的高保真度和用于计算绿色功能的近似值，是理论的关键基准，并表明应准确预测其他材料的特性；我们证明了导热率。
Phonon lifetimes are a key component of quasiparticle theories of transport, yet first-principles lifetimes are rarely directly compared to inelastic neutron scattering (INS) results. Existing comparisons show discrepancies even at temperatures where perturbation theory is expected to be reliable. In this work, we demonstrate that the reciprocal space voxel ($q$-voxel), which is the finite region in reciprocal space required in INS data analysis, must be explicitly accounted for within theory in order to draw a meaningful comparison. We demonstrate accurate predictions of peak widths of the scattering function when accounting for the $q$-voxel in CaF$_2$ and ThO$_2$. Passing this test implies high fidelity of the phonon interactions and the approximations used to compute the Green's function, serving as critical benchmark of theory, and indicating that other material properties should be accurately predicted; which we demonstrate for thermal conductivity.
