标题： 准粒子干涉格林函数计算中的中间带分析 显示英文标题

标题： Intermediate band analysis in Green's functions calculations of quasiparticle interference

摘要： 使用扫描隧道显微镜（STM）测量材料表面上准粒子散射图案现在已成为一种成熟的技术，用于获取固体的动量分辨电子能带结构。 然而，由于这些准粒子干涉（QPI）图案反映了与能带动量差异相关的空间变化，而不是动量本身，因此它们的解释通常依赖于与简单几何模型的比较，例如联合态密度（JDOS）或格林函数的卷积。 在本文中，我们强调了格林函数和JDOS结果之间的非直观差异。 为了理解这些差异的来源，我们使用费曼参数化技术分析了格林函数的卷积，并引入了一种称为中间带分析的框架。 这种方法使我们能够基于电子群速度推导出带间QPI的简单选择规则。 将中间带分析与实验联系起来，我们考虑了FeSe1-xSx中测量到的实验玻戈留波夫QPI图案，这些图案最近被用来证明超导能隙的高度各向异性，表明超导性由向列涨落介导[1]。 计算得到的格林函数卷积再现了实验中观察到的费米能级上下QPI图案强度的粒子-空穴不对称性。 最后，我们展示了中间带分析在追溯这种不对称性的起源至超导态的相干因子效应方面的实用性。 显示英文摘要

摘要： The measurement of quasiparticle scattering patterns on material surfaces using scanning tunneling microscopy (STM) is now an established technique for accessing the momentum-resolved electronic band structure of solids. However, since these quasiparticle interference (QPI) patterns reflect spatial variations related to differences in the band momenta rather than the momenta themselves, their interpretation often relies on comparisons with simple geometrical models such as the joint density of states (JDOS) or with the convolution of Green's functions. In this paper, we highlight non-intuitive differences between Green's function and JDOS results. To understand the origin of these discrepancies, we analyze the convolution of Green's functions using the Feynman parametrization technique and introduce a framework that we call the intermediate band analysis. This approach allows us to derive simple selection rules for interband QPI, based on electron group velocities. Connecting the intermediate band analysis with the experiment, we consider experimental Bogoliubov QPI patterns measured for FeSe1-xSx, which were recently used to demonstrate a highly anisotropic superconducting gap, indicating superconductivity mediated by nematic fluctuations [1]. The calculated Green's functions convolutions reproduce the particle-hole asymmetry in the intensity of QPI patterns across the Fermi level observed in experiments. Finally, we demonstrate the utility of intermediate band analysis in tracing the origin of this asymmetry to a coherence factor effect of the superconducting state.