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arXiv 2011.04509cond-mat.str-elcond-mat.mtrl-sci
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关联金属中共振非弹性X射线散射的描述

Description of resonant inelastic x-ray scattering in correlated metals

Keith Gilmore, Jonathan Pelliciari, Yaobo Huang, Joshua J. Kas, Marcus Dantz, Vladimir N. Strocov, Shigeru Kasahara, Yuji Matsuda, Tanmoy Das, Takasada Shibauchi, Thorsten Schmitt

摘要:

为了充分利用共振非弹性X射线散射(RIXS)的潜力和多功能性,必须开发通过计算解释不同RIXS贡献的能力,包括相关材料的第一原理对动量转移的依赖性。为了实现这一目标,我们提出了一种新的方法来计算完整的RIXS响应的相关金属在一个公正的方式。通过比较的测量和计算,调整的入射光子能量的Fe L $_3$吸收共振的示例性材料BaFe $_2$作为$_2$的宽的一部分,我们表明,RIXS响应BaFe $_2$作为$_2$占主导地位的直接通道的贡献,包括拉曼响应低于阈值,我们解释为有限的芯孔寿命加宽的结果。计算最初是在第一性原理Bethe-Salpeter框架内进行的,然后我们通过与中间态激发的有效谱函数进行卷积来显着改进该框架。我们构造这个光谱函数,也从第一性原理,通过采用累积展开的格林函数和执行实时依赖于时间的密度泛函理论计算的电子系统的响应的扰动的中间态激发。重要的是,这使我们能够从第一原理评估间接RIXS响应,解释晶体结构的完整周期性并依赖于动量转移。

英文摘要:

To fully capitalize on the potential and versatility of resonant inelastic x-ray scattering (RIXS), it is essential to develop the capability to interpret different RIXS contributions through calculations, including the dependence on momentum transfer, from first-principles for correlated materials. Toward that objective, we present new methodology for calculating the full RIXS response of a correlated metal in an unbiased fashion. Through comparison of measurements and calculations that tune the incident photon energy over a wide portion of the Fe L$_3$ absorption resonance of the example material BaFe$_2$As$_2$, we show that the RIXS response in BaFe$_2$As$_2$ is dominated by the direct channel contribution, including the Raman-like response below threshold, which we explain as a consequence of the finite core-hole lifetime broadening. Calculations are initially performed within the first-principles Bethe-Salpeter framework, which we then significantly improve by convolution with an effective spectral function for the intermediate-state excitation. We construct this spectral function, also from first-principles, by employing the cumulant expansion of the Green's function and performing a real-time time dependent density functional theory calculation of the response of the electronic system to the perturbation of the intermediate-state excitation. Importantly, this allows us to evaluate the indirect RIXS response from first-principles, accounting for the full periodicity of the crystal structure and with dependence on the momentum transfer.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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