Spontaneous Electric Polarization in Graphene Polytypes
Spontaneous Electric Polarization in Graphene Polytypes
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DOI：
10.1002/apxr.202300095
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
Simon Salleh Atri;W. Cao;Barash Alon;N. K. Roy;Maayan Vizner Stern;V. Falko;M. Goldstein;L. Kronik;M. Urbakh;O. Hod;M. Shalom
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文献类型：
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作者：
Simon Salleh Atri;W. Cao;Barash Alon;N. K. Roy;Maayan Vizner Stern;V. Falko;M. Goldstein;L. Kronik;M. Urbakh;O. Hod;M. Shalom
最近在多层货车德瓦尔斯堆叠材料中观察到自发电极化，其产生于具有两个或更多组成物种的单位晶胞中的对称性破缺，或单原子物种材料中的非中心对称层内原子位移。在这里，它表明，即使是元素晶体，由一种类型的原子和非极性和中心对称层组成，表现出电极化，如果安排在一个适当的三维结构。在此，针对非极性石墨烯片的混合堆叠的四层多型体证明了该概念。令人惊讶的是，发现室温离面电极化随着外部静电空穴掺杂而增加，而不是由于屏蔽而减少。使用第一性原理计算，以及自洽紧束缚模型，极化的出现解释层间电荷重排和掺杂依赖性的门控诱导层间电荷转移。因此，这种新发现的固有极化可能为设计石墨烯多型体对外部场的电子响应提供新的场所。
Spontaneous electric polarization is recently observed in multilayered van der Waals stacked materials, arising from a symmetry breaking in a unit cell with two or more constituent species, or non‐centrosymmetric intra‐layer atom displacement in single‐atom‐species materials. Here, it is shown that even elemental crystals, consisting of one type of atom and composed of non‐polar and centrosymmetric layers, exhibit electric polarization if arranged in an appropriate three‐dimensional architecture. This concept is demonstrated here for mixed‐stacking tetra‐layer polytypes of non‐polar graphene sheets. Surprisingly, it is find that the room temperature out‐of‐plane electric polarization increases with external electrostatic hole doping, rather than decreases with it owing to screening. Using first‐principles calculations, as well as a self‐consistent tight‐binding model, the emergence of polarization is explain in terms of inter‐layer charge rearrangement and the doping dependence in terms of gating‐induced inter‐layer charge transfer. This newly discovered intrinsic polarization may therefore offer new venues for designing the electronic response of graphene‐based polytypes to external fields.