论文标题
多层FESE膜中错位网格的旋转以及通过轨道选择性隧道的电子态域的可视化
Rotation of the dislocation grid in multilayer FeSe films and visualization of electronic nematic domains via orbital-selective tunneling
论文作者
论文摘要
了解基于Fe的高温超导体中结构和电子对称性破坏的相互作用仍然引起了人们的关注。在这项工作中，我们使用分子束外延，在一系列厚度中种植应变图案的多层FESE薄膜。我们研究了使用扫描隧道显微镜和光谱法的电子列域和空间变化应变的形成。我们直接看到边缘的形成，从而导致膜中产生二维边缘位错网络。有趣的是，我们观察到位错网络的45度内旋作为膜厚度的函数，从而沿不同方向产生反对称应变。这导致电子列域和反对称应变之间的耦合比不同。最后，我们能够通过揭示两个区域之间差分电导图的较小能量依赖性差异来区分不同的正交列内域。这可以通过轨道选择性尖端样本隧道来解释。我们的观察结果为外延薄膜中的脱位网络形成带来了新的见解，并提供了另一个纳米级工具，以探索基于Fe的超导体中的电子nematicition。
Understanding the interplay of structural and electronic symmetry breaking in Fe-based high temperature superconductors remains of high interest. In this work we grow strain-patterned multilayer FeSe thin films in a range of thicknesses using molecular beam epitaxy. We study the formation of electronic nematic domains and spatially-varying strain using scanning tunneling microscopy and spectroscopy. We directly visualize the formation of edge dislocations that give rise to a two-dimensional edge dislocation network in the films. Interestingly, we observe a 45 degree in-plane rotation of the dislocation network as a function of film thickness, yielding antisymmetric strain along different directions. This results in different coupling ratios between electronic nematic domains and antisymmetric strain. Lastly, we are able to distinguish between different orthogonal nematic domains by revealing a small energy-dependent difference in differential conductance maps between the two regions. This could be explained by orbital-selective tip-sample tunneling. Our observations bring new insights into the dislocation network formation in epitaxial thin films and provide another nanoscale tool to explore electronic nematicity in Fe-based superconductors.
