ZrSe$_3$表面的晶面与厚度依赖的带边对齐：含自旋轨道耦合的杂化泛函计算
Facet- and thickness-dependent band-edge alignment at ZrSe\texorpdfstring{$_3$}{3} surfaces: hybrid-functional calculations with spin-orbit coupling
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中文总结 AI 辅助
通过杂化泛函计算，研究了ZrSe$_3$四个表面的表面能与带边对齐，发现(210)晶面带隙随厚度显著减小，且Se-Se二聚体的扭曲决定电子性质，为析氢活性提供了理论解释。
中文摘要 AI 辅助
过渡金属三硫族化物MX$_3$是准一维范德华材料，其层通过横向链结合形成，从而具有层间解理面和面内电子各向异性。其中，ZrSe$_3$在环境条件下稳定且具有半导体性质。剥离晶体暴露出四个结晶面，对单个晶体的电催化测量将析氢活性归因于高能(210)晶面而非基面。这些非基面尚未被表征，因为现有计算仅处理体相晶体或独立基面单层。在此，我们使用含色散修正的半局域泛函计算了这四个表面的表面能和平衡形貌，并使用包含自旋轨道耦合的HSE06杂化泛函计算了它们的带边对齐。表面能跨越近一个数量级，从(001)的0.097焦耳每平方米到(010)的0.869焦耳每平方米，Wulff形貌暴露了四个观测面，面积分数分别为17.1%、4.4%、71.4%和7.0%。电离势在不同晶面间变化0.45电子伏特，电子亲和能变化0.80电子伏特，(210)的带隙在10至23埃之间从1.43电子伏特降至0.94电子伏特，而(010)保持金属性。这些晶面根据切割是否保留或扭曲Se-Se二聚体而区分，扭曲的二聚体集中了前沿态。由于相同的二聚体控制着MX$_3$家族的体相电子结构，该判据可推广到相关的三硫族化物。
英文摘要
Transition-metal trichalcogenides MX$_3$ are quasi-one-dimensional van der Waals materials whose layers form through lateral chain binding, giving them an interlayer cleavage plane and in-plane electronic anisotropy. Among them, ZrSe$_3$ is stable under ambient conditions and semiconducting. Exfoliated crystals expose four crystallographic planes, and electrocatalytic measurements on an individual crystal assigned the hydrogen evolution activity to the high-energy (210) facet rather than to the basal plane. Those non-basal surfaces remain uncharacterized, since the available calculations treat either the bulk crystal or the free-standing basal monolayer. Here, we compute the surface energies and the equilibrium morphology of these four surfaces with a dispersion-corrected semilocal functional, and their band-edge alignment with the HSE06 hybrid functional including spin-orbit coupling. The surface energies span nearly an order of magnitude, from \SI{0.097}{\joule\per\meter\squared} for (001) to \SI{0.869}{\joule\per\meter\squared} for (010), and the Wulff shape exposes the four observed planes with area fractions of \SI{17.1}{\percent}, \SI{4.4}{\percent}, \SI{71.4}{\percent}, and \SI{7.0}{\percent}. The ionization potential varies by \SI{0.45}{\electronvolt} between facets and the electron affinity by \SI{0.80}{\electronvolt}, the gap of (210) falls from 1.43 to \SI{0.94}{\electronvolt} between 10 and \SI{23}{\angstrom}, and (010) remains metallic. The facets separate according to whether the cut preserves or distorts the Se-Se dimer, and the distorted dimers concentrate the frontier states. Because the same dimer governs the bulk electronic structure of the MX$_3$ family, the criterion transfers to the related trichalcogenides.
发表机构
- College UnB Planaltina, University of Brasília（巴西利亚大学普拉蒂纳学院）
- NanoEngineering Laboratory, University of Brasília（巴西利亚大学纳米工程实验室）
- Applied Physics Department and Center for Computational Engineering and Sciences, State University of Campinas（坎皮纳斯州立大学应用物理系与计算科学与工程中心）
- Department of Materials Science and Nanoengineering, Rice University（莱斯大学材料科学与纳米工程系）
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