Electronic properties of 8-Pmmn borophene
Electronic properties of 8-Pmmn borophene
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DOI：
10.1103/physrevb.93.241405
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发表时间：
2016-06-15
影响因子：
3.7
通讯作者：
Littlewood, Peter B.
中科院分区：
文献类型：
--
作者：
Lopez-Bezanilla, Alejandro;Littlewood, Peter B.
报道了用第一性原理方法对单层8-PmMn硼烯进行的计算，揭示了二维材料中前所未有的电子性质。基于Born有效电荷分析，8-PmMn硼烯是第一个表现出具有实质性离子特征的两个亚晶格的单元单分子膜材料。观测到的狄拉克圆锥实际上是由唯一的四个原子组成的一个不等价的亚晶格的p(Z)轨道形成的，产生了一个在拓扑上等同于扭曲的石墨烯的六角形网络。这一效应的一个重要物理结果包括通过外部剪应力将金属8-PmMn硼烯转化为间接带隙半导体的可能性。声子频率分析支持应变结构的稳定性。狄拉克锥体只对费米能级电子活跃的不等价亚晶格中的空位形成敏感。
First-principles calculations on monolayer 8-Pmmn borophene are reported to reveal unprecedented electronic properties in a two-dimensional material. Based on a Born effective charge analysis, 8-Pmmn borophene is the first single-element-based monolayered material exhibiting two sublattices with substantial ionic features. The observed Dirac cones are actually formed by the p(z) orbitals of one of the inequivalent sublattices composed of uniquely four atoms, yielding an underlying hexagonal network topologically equivalent to distorted graphene. A significant physical outcome of this effect includes the possibility of converting metallic 8-Pmmn borophene into an indirect band gap semiconductor by means of external shear stress. The stability of the strained structures are supported by a phonon frequency analysis. The Dirac cones are sensitive to the formation of vacancies only in the inequivalent sublattice electronically active at the Fermi level.