Edge States of Bi Nanoribbons on Bi Substrates: First-Principles Density Functional Study
Edge States of Bi Nanoribbons on Bi Substrates: First-Principles Density Functional Study
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DOI：
10.1143/jjap.51.025201
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发表时间：
2012-01
影响因子：
1.5
通讯作者：
H. Kotaka;F. Ishii;M. Saito;T. Nagao;S. Yaginuma
中科院分区：
文献类型：
--
作者：
H. Kotaka;F. Ishii;M. Saito;T. Nagao;S. Yaginuma
利用完全相对论第一性原理计算，研究了Bi（001）纳米带的边缘态。我们发现，独立之形铋纳米带（ZBNRs）在费米能周围有两条自旋简并带，其波函数在边缘局域化。波函数在区域边界的边缘处明显局部化，随着波数的减少而发生离域。在Bi基板上的ZBNR，反演对称性被打破。结果，自旋简并带分裂，因而在费米能级附近的态密度具有广泛的分布；因此，电子结构有望稳定。由于费米能附近的边缘状态，沿边缘线的传导是预期的。然而，在Bi衬底上的ZBNR中，在独立式ZBNR中预测的拓扑绝缘体并没有实现。
By using fully relativistic first-principles calculations, we study edge states of the Bi(001) nanoribbons. We find that freestanding zigzag bismuth nanoribbons (ZBNRs) have two spin degenerate bands around the Fermi energy, whose wave functions are localized at the edges. The wave functions are sharply localized at the edges at the zone boundary and become delocalized as the wave number decreases. In the case of the ZBNR on Bi substrates, the inversion symmetry is broken. As a result, the spin degenerate bands split and thus the density of states near the Fermi level has broad distributions; therefore, the electronic structures are expected to be stabilized. Because of the edge state near the Fermi energy, conduction along the edge lines is expected. However, the topological insulator predicted in the case of the freestanding ZBNR is not achieved in the case of the ZBNR on Bi substrates.