Exfoliation of natural van der Waals heterostructures to a single unit cell thickness.
Exfoliation of natural van der Waals heterostructures to a single unit cell thickness.
复制标题
DOI：
10.1038/ncomms14410
复制
发表时间：
2017-02-13
影响因子：
16.6
通讯作者：
Dryfe RA
中科院分区：
文献类型：
--
作者：
Velický M;Toth PS;Rakowski AM;Rooney AP;Kozikov A;Woods CR;Mishchenko A;Fumagalli L;Yin J;Zólyomi V;Georgiou T;Haigh SJ;Novoselov KS;Dryfe RA
范德华晶体中弱的层间相互作用有利于它们机械剥离为单层和少层二维材料，这些材料通常表现出块体形式所不存在的引人注目的物理现象。在这里，我们利用机械剥落来生产二维形式的矿物铁橄榄石，并表明化学物质在亚纳米尺度上相分离成离散层，有利于铁橄榄石的层状结构和基底解理降至单个晶胞厚度。这种行为可能在更广泛的复杂矿物家族中很常见，并且可以用于范德华异质结构的一步合成，作为单个二维晶体的人工堆叠的替代方案。我们展示了剥离晶体的 p 型电导率和显着的电化学性能，显示了一系列应用的前景，并使用镁钙石电子能带结构的密度泛函理论计算来合理化实验结果。层状材料通过弱范德华力结合在一起，促进逐层裂解。在这里，作者展示了天然存在的铁橄榄石矿物异质结构的机械剥落，该异质结构具有 p 型导电性和卓越的电化学性能。
Weak interlayer interactions in van der Waals crystals facilitate their mechanical exfoliation to monolayer and few-layer two-dimensional materials, which often exhibit striking physical phenomena absent in their bulk form. Here we utilize mechanical exfoliation to produce a two-dimensional form of a mineral franckeite and show that the phase segregation of chemical species into discrete layers at the sub-nanometre scale facilitates franckeite's layered structure and basal cleavage down to a single unit cell thickness. This behaviour is likely to be common in a wider family of complex minerals and could be exploited for a single-step synthesis of van der Waals heterostructures, as an alternative to artificial stacking of individual two-dimensional crystals. We demonstrate p-type electrical conductivity and remarkable electrochemical properties of the exfoliated crystals, showing promise for a range of applications, and use the density functional theory calculations of franckeite's electronic band structure to rationalize the experimental results. Layered materials are held together by weak van der Waals forces facilitating layer-by-layer cleavage. Here, the authors demonstrate mechanical exfoliation of a naturally occurring franckeite mineral heterostructure, possessing p-type conductivity and remarkable electrochemical properties.