Topological effects of three-dimensional porous graphene on Dirac quasiparticles
Topological effects of three-dimensional porous graphene on Dirac quasiparticles
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发表时间：
2020-02
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通讯作者：
T. Okamoto;Yoshikazu Ito;N. Nagamura;Keishi Akada;T. Fujita;Y. Kawano
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作者：
T. Okamoto;Yoshikazu Ito;N. Nagamura;Keishi Akada;T. Fujita;Y. Kawano
本文报道了孔径可调的三维（3D）多孔石墨烯和狄拉克准粒子的保留二维石墨烯系统对其电性能的拓扑效应。这种3D结构的特点是平滑互连的石墨烯片的固有曲率，没有边缘，其结构和性能可以通过其孔径来控制。通过磁阻测量研究了孔径对电传输特性的影响。我们观察到，随着温度的降低，具有小孔的 3D 石墨烯表现出向弱局域化的转变。与基于量子校正的理论的比较表明，本征曲率的增加显着诱发了层间散射事件，从而破坏了手性。这种层间散射率的增加源于3D石墨烯独特的拓扑效应，即形成高曲率和由此产生的手性混合所需的拓扑缺陷。我们还讨论了由高空间分辨 X 射线光电子光谱成像发现的微观化学键态引起的散射过程，以支持我们发现的有效性。
This paper reports on the topological effects of three-dimensional (3D) porous graphene with tunable pore sizes and a preserved 2D graphene system of Dirac quasiparticles on its electrical properties. This 3D architecture is characterized by the intrinsic curvature of smoothly interconcnected graphene sheets without edges, the structures and properties of which can be controlled with its pore sizes. The impact of pore size on the electrical transport properties was investigated through magnetoresistance measurements. We observed that 3D graphene with small pores exhibits transitioning to weak localization with decreasing temperature. The comparison with the theory based on the quantum correction clarified that an increase in the intrinsic curvature significantly induces the intervalley scattering event, which breaks the chirality. This increase in the intervalley scattering rate originates from the unique topological effects of 3D graphene, i.e., the topological defects required to form the high curvature and the resulting chirality mixing. We also discuss the scattering processes due to microscopic chemical bonding states as found by high spatial-resolved X-ray photoemission spectral imaging, to support the validity of our finding.