Uniaxially Aligned 1D Sandwich-Molecular Wires: Electronic Structure and Magnetism
Uniaxially Aligned 1D Sandwich-Molecular Wires: Electronic Structure and Magnetism
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DOI：
10.1021/acs.jpcc.1c10625
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发表时间：
2022-02-17
影响因子：
3.7
通讯作者：
Michely, Thomas
中科院分区：
文献类型：
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作者：
Kraus, Stefan;Herman, Alexander;Michely, Thomas
用Ir(110)在石墨烯的云纹上原位生长了由Eu和环辛四烯(CoT)组成的三明治分子线。莫尔模板单层EuCot纳米线地毯和多层薄膜的单轴排列，EuCot线轴沿Ir衬底的[001]方向。利用角度分辨光电子能谱研究了丝毯薄膜的能带结构。虽然实验上没有观察到p导带，但我们发现在费米能级以下有一个1.85 eV的平带。利用密度泛函理论和X射线光电子能谱，并在夹心分子线中用Ba2+取代Eu2+，得出平带是由Eu4f态与Eu5d态弱混合，与Cotpi态略有重叠而产生的。用X射线磁性圆二色谱表征了EuCot丝毯薄膜的低温磁性能。发现了沿导线的易轴磁化的明显证据。
Sandwich-molecular wires consisting of europium and cyclooctatetraene (Cot) were grown in situ on the moire ' of graphene with Ir(110). The moire templates a uniaxial alignment of monolayer EuCot nanowire carpets and multilayer films with the EuCot wire axis along the [001] direction of the Ir substrate. Using angle-resolved photoemission spectroscopy, we investigate the band structure of the wire carpet films. While p-derived bands were not observed experimentally, we find a flat band 1.85 eV below the Fermi energy. Using density-functional theory and X-ray photoelectron spectroscopy and replacing europium through barium in the sandwich-molecular wires, it is concluded that the flat band is derived from Eu 4f states weakly mixed with Eu 5d states and slightly overlapping with Cot pi states. X-ray magnetic circular dichroism is employed to characterize the magnetic properties of the EuCot wire carpet films at low temperatures. Clear evidence for an easy-axis magnetization along the wires is found.