Electrical Conduction at the Interface between Insulating van der Waals Materials
Electrical Conduction at the Interface between Insulating van der Waals Materials
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DOI：
10.1002/adfm.201900354
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发表时间：
2019-03
影响因子：
19
通讯作者：
Yuta Kashiwabara;M. Nakano;Yuji Nakagawa;Yue Wang;H. Matsuoka;Y. Iwasa
中科院分区：
文献类型：
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作者：
Yuta Kashiwabara;M. Nakano;Yuji Nakagawa;Yue Wang;H. Matsuoka;Y. Iwasa
2D材料的涌现性质吸引了凝聚态物理和材料科学的相当大的兴趣，由于他们的显着特点，在他们的散装同行失踪。拓宽材料的范围以拓展研究领域的视野是该研究领域的一个主流，而开发不同二维材料之间的功能界面是另一个不可或缺的研究方向。在这里，演示了绝缘2D材料之间界面处的导电性的出现。通过分子束外延发展了一种新的货车德瓦耳斯异质结构，它由两组绝缘的过渡金属二硫属化合物，VI族WSe 2和IV族TMSe 2（TM = Zr，Hf）组成，并且发现这些异质结构是高度导电的，尽管所有的组成材料都是高度绝缘的。WSe 2/ZrSe 2界面比WSe 2/HfSe 2界面表现出更多的导电行为，这可以通过考虑组成材料之间的能带对准来理解。此外，通过在异质结构制造过程中增加Se通量，WSe 2/ZrSe 2界面变得更加导电，达到接近金属的行为。晶体质量的进一步改善以及探索不同的材料组合有望导致金属导电，从而在货车德瓦尔斯异质结构中提供新的功能。
Emergent properties of 2D materials attract considerable interest in condensed matter physics and materials science due to their distinguished features that are missing in their bulk counterparts. A mainstream in this research field is to broaden the scope of material to expand the horizons of the research area, while developing functional interfaces between different 2D materials is another indispensable research direction. Here, the emergence of electrical conduction at the interface between insulating 2D materials is demonstrated. A new class of van der Waals heterostructures consisting of two sets of insulating transition‐metal dichalcogenides, group‐VI WSe2 and group‐IV TMSe2 (TM = Zr, Hf), is developed via molecular‐beam epitaxy, and it is found that those heterostructures are highly conducting although all the constituent materials are highly insulating. The WSe2/ZrSe2 interface exhibits more conducting behavior than the WSe2/HfSe2 interface, which can be understood by considering the band alignments between constituent materials. Moreover, by increasing Se flux during heterostructure fabrication, the WSe2/ZrSe2 interface becomes more conducting, reaching nearly metallic behavior. Further improvement of the crystalline quality as well as exploring different material combinations are expected to lead to metallic conduction, providing a novel functionality emerging at van der Waals heterostructures.