Rotation of the dislocation grid in multilayer FeSe films and visualization of electronic nematic domains via orbital-selective tunneling
Rotation of the dislocation grid in multilayer FeSe films and visualization of electronic nematic domains via orbital-selective tunneling
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DOI：
10.1103/physrevmaterials.6.124802
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发表时间：
2022-11
影响因子：
3.4
通讯作者：
Zheng Ren;Hong Li;He Zhao;Shrinkhala Sharma;I. Zeljkovic
中科院分区：
文献类型：
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作者：
Zheng Ren;Hong Li;He Zhao;Shrinkhala Sharma;I. Zeljkovic
了解铁基高温超导体中结构和电子对称性破缺的相互作用仍然是人们非常感兴趣的问题。在这项工作中，我们使用分子束外延技术在一定厚度范围内生长应变图像化多层FeSe薄膜。我们利用扫描隧道显微镜和光谱学研究了电子向列畴和空间变化应变的形成。我们直接可视化了在薄膜中产生二维边缘位错网络的边缘位错的形成。有趣的是，我们观察到位错网络的45度平面内旋转是薄膜厚度的函数，沿不同方向产生反对称应变。这导致了电子向列域和反对称应变之间的不同耦合比。最后，我们能够通过揭示两个区域之间的微分电导图中的小能量依赖差异来区分不同的正交向列域。这可以用轨道选择性尖端样品隧穿来解释。我们的观察为外延薄膜中的位错网络的形成提供了新的见解，并为探索铁基超导体中的电子向列性提供了另一种纳米尺度的工具。
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.