Huang Zhi-Quan, Chen Wei-Chih, Macam Gennevieve M, Crisostomo Christian P, Huang Shin-Ming, Chen Rong-Bin, Albao Marvin A, Jang Der-Jun, Lin Hsin, Chuang Feng-Chuan
Department of Physics, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan.
Center of General Studies, National Kaohsiung Marine University, Kaohsiung, 811, Taiwan.
Nanoscale Res Lett. 2018 Feb 7;13(1):43. doi: 10.1186/s11671-017-2424-y.
The abounding possibilities of discovering novel materials has driven enhanced research effort in the field of materials physics. Only recently, the quantum anomalous hall effect (QAHE) was realized in magnetic topological insulators (TIs) albeit existing at extremely low temperatures. Here, we predict that MPn (M =Ti, Zr, and Hf; Pn =Sb and Bi) honeycombs are capable of possessing QAH insulating phases based on first-principles electronic structure calculations. We found that HfBi, HfSb, TiBi, and TiSb honeycomb systems possess QAHE with the largest band gap of 15 meV under the effect of tensile strain. In low-buckled HfBi honeycomb, we demonstrated the change of Chern number with increasing lattice constant. The band crossings occurred at low symmetry points. We also found that by varying the buckling distance we can induce a phase transition such that the band crossing between two Hf d-orbitals occurs along high-symmetry point K2. Moreover, edge states are demonstrated in buckled HfBi zigzag nanoribbons. This study contributes additional novel materials to the current pool of predicted QAH insulators which have promising applications in spintronics.
发现新型材料的众多可能性推动了材料物理领域研究工作的加强。直到最近，量子反常霍尔效应（QAHE）才在磁性拓扑绝缘体（TI）中实现，尽管其存在于极低温度下。在此，我们基于第一性原理电子结构计算预测，MPn（M = Ti、Zr和Hf；Pn = Sb和Bi）蜂窝结构能够拥有量子反常霍尔绝缘相。我们发现，在拉伸应变的作用下，HfBi、HfSb、TiBi和TiSb蜂窝结构体系具有量子反常霍尔效应，其最大带隙为15毫电子伏特。在低屈曲的HfBi蜂窝结构中，我们展示了陈数随晶格常数增加的变化。能带交叉出现在低对称点。我们还发现，通过改变屈曲距离，可以诱导相变，使得两个Hf d轨道之间的能带交叉沿着高对称点K2发生。此外，在屈曲的HfBi锯齿形纳米带中展示了边缘态。这项研究为当前预测的量子反常霍尔绝缘体库增添了新的材料，这些材料在自旋电子学中具有广阔的应用前景。
