Ab initio study of energy-band modulation in graphene-based two-dimensional layered superlattices
Ab initio study of energy-band modulation in graphene-based two-dimensional layered superlattices
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DOI：
10.1039/c2jm35652j
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发表时间：
2012-10
影响因子：
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通讯作者：
Yang Xu;Yunlong Liu;Huabin Chen;Xiao Lin;Shisheng Lin;Bin Yu;Jikui Luo
中科院分区：
文献类型：
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作者：
Yang Xu;Yunlong Liu;Huabin Chen;Xiao Lin;Shisheng Lin;Bin Yu;Jikui Luo
周期性堆叠的石墨烯及其绝缘同质同晶为在原子尺度上实现高功能超晶格提供了一个迷人的结构元素，这为设计纳米电子和光子器件提供了可能性。使用密度泛函理论（DFT）计算，我们证明了各种类型的超晶格可以通过交替堆叠二维（2D）材料，即石墨烯，六方氮化硼（h-BN），氢化石墨烯，氟化石墨烯。发现叠层超晶格中的能带对势垒宽度比传统的III-V族半导体超晶格中的能带更敏感。当在每个周期内向势垒添加多个原子层时，相邻势威尔斯中电子波函数的耦合可以显著降低，从而导致连续子带退化为量子化能级。当阱宽变化时，威尔斯沿着L-M方向的势阱中的能级与沿着K-H方向的势阱中的能级表现不同。我们的研究结果表明，原子层超晶格中的量子化能态可以通过修改每个单独的势垒/阱层来有效地调节，从而实现原子尺度的材料工程。
Periodically stacked graphene and its insulating isomorph provide a fascinating structural element in implementing highly functional superlattices at the atomic scale, which offers possibilities in designing nanoelectronic and photonic devices. Using density functional theory (DFT) calculations, we demonstrate that various types of superlattices can be obtained by stacking two-dimensional (2D) materials alternately, namely, graphene, hexagonal boron nitride (h-BN), hydrogenated graphene, and fluorinated graphene. The energy band in layer-stacked superlattices is found to be more sensitive to the barrier width than that in conventional III–V semiconductor superlattices. When adding more than one atomic layer to the barrier in each period, the coupling of electronic wavefunctions in neighboring potential wells can be significantly reduced, which leads to the degeneration of continuous subbands into quantized energy levels. When varying the well width, the energy levels in the potential wells along the L-M direction behave distinctly from those along the K-H direction. Our results indicate that the quantized energy states in atomic-layered superlattices can be effectively tuned by modifying each individual barrier/well layer, enabling atomic-scale material engineering.