五边形石墨烯中的四方墨西哥帽色散与可切换半金属态及多重各向异性外尔费米子
Tetragonal Mexican-Hat Dispersion and Switchable Half-Metal State with Multiple Anisotropic Weyl Fermions in Penta-Graphene
AI总结：
本文通过第一性原理计算发现五边形石墨烯在空穴掺杂下可转变为室温稳定的铁磁半金属，并在应变下实现多种各向异性外尔态，为碳基自旋电子学提供了新途径。
摘要：
在过去几十年中，不断扩展的二维碳同素异形体库为未来碳基电子学带来了广泛的奇异性质。然而，由于价电子成对排布，已知的同素异形体本质上都是非磁性的。基于已报道的二维碳结构数据库和第一性原理计算，我们在此证明，在著名的同素异形体五边形石墨烯中可以获得固有铁磁性。该材料具有独特的墨西哥帽型价带边，从而产生范霍夫奇点和电子不稳定性。在适度的空穴掺杂（可通过电解质栅极实现）诱导下，半导体性五边形石墨烯可以转变为不同的铁磁半金属，具有室温稳定性和可切换的自旋方向。特别地，在适当应变下，自旋向下半金属的一个可观能量窗口内可以发现多重各向异性外尔态，包括I型和II型外尔锥以及杂化准外尔节线环。这些发现不仅确定了一种有前景的碳同素异形体，可用于碳基自旋电子器件获得固有磁性，而且突显了通过结合电子手段和力学手段实现不同外尔态的可能性。
英文摘要：
In past decades, the ever-expanding library of 2D carbon allotropes has yielded a broad range of exotic properties for the future carbon-based electronics. However, the known allotropes are all intrinsic nonmagnetic due to the paired valence electrons configuration. Based on the reported 2D carbon structure database and first-principles calculations, herein we demonstrate that inherent ferromagnetism can be obtained in the prominent allotrope, penta-graphene, which has an unique Mexican-hat valence band edge, giving rise to van Hove singularities and electronic instability. Induced by modest hole-doping, being achievable in electrolyte gate, the semiconducting pentagraphene can transform into different ferromagnetic half-metals with room temperature stability and switchable spin directions. In particular, multiple anisotropic Weyl states, including type-I and type-II Weyl cones and hybrid quasi Weyl nodal loop, can be found in a sizable energy window of spin-down half-metal under proper strains. These findings not only identify a promising carbon allotrope to obtain the inherent magnetism for carbon-based spintronic devices, but highlight the possibility to realize different Weyl states by combining the electronic and mechanical means as well.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
