论文标题
在差异相对比度扫描透射式电子显微镜下抑制动力学衍射伪像，通过进动的远程电磁场
Suppressing dynamical diffraction artefacts in differential phase contrast scanning transmission electron microscopy of long-range electromagnetic fields via precession
论文作者
论文摘要
在差异对比度扫描透射电子显微镜（DPC-STEM）中，由于样品厚度和局部晶体方向的变化（由于样品弯曲）而导致的动力学衍射变异性可产生与该技术探测的远程电磁场所产生的对比度。通过模拟，我们探讨了这些动态衍射伪像的规模，并引入了一个指标，以使其对对比度的混淆贡献的大小。我们表明，对几毫米的角度范围的进动可以抑制这种混淆的对比度，而对比度是一个一到二的数量级。我们的勘探中心围绕[011]区域轴附近的GAA案例研究，使用探测器形成的孔径半径在300 keV处为0.1 MRAD的阶，但预计所使用的趋势和方法将更普遍地应用。
In differential phase contrast scanning transmission electron microscopy (DPC-STEM), variability in dynamical diffraction resulting from changes in sample thickness and local crystal orientation (due to sample bending) can produce contrast comparable to that arising from the long-range electromagnetic fields probed by this technique. Through simulation we explore the scale of these dynamical diffraction artefacts and introduce a metric for the magnitude of their confounding contribution to the contrast. We show that precession over an angular range of a few milliradian can suppress this confounding contrast by one-to-two orders of magnitude. Our exploration centres around a case study of GaAs near the [011] zone-axis orientation using a probe-forming aperture semiangle on the order of 0.1 mrad at 300 keV, but the trends found and methodology used are expected to apply more generally.
