Title: Tunable electronic properties of germanene and two-dimensional group-III phosphides heterobilayers Show Chinese title

Title: 锗烯和二维 III 族磷化物异质结的可调电子性质

Abstract: In this research work, the 2D structure of the germanene layer is compounded with 2D group-III phosphides: AlP and GaP. The planar structure of AlP and low-buckled GaP have been taken to form the bilayer patterns. In each case, three stacking patterns are considered, and their relaxed interlayer distance and binding energy have been reported. The binding energy being around in the range between ~150 to 210 meV shows the existence of weak van der Waals interactions between the layers. The heterostructures containing germanene and these two phosphides show an opening of a large indirect bandgap of magnitude range of ~200 meV to 600 meV, which can be tuned by changing interlayer distance and by incorporating bi-axial compressive and tensile strain. Although their normal bandgap, which significantly changes with SOC, is an indirect one, whilst tunning the interlayer distance band gap jumps from unsymmetrical point to symmetrical Dirac cones and becomes direct on K points. The charge carrier mostly concentrates on the p-orbitals of the germanene in the conduction regions; thus, the electrical properties of germanene will be retained, and the carrier will provide a much faster device response property. The absence of the phosphides influence makes them the intended substrate for growing the germanene layer on top of that. Again, due to the bandgap at Dirac cones being opened and jumps between the Dirac cones and band gap changes with SOC tropological insulator can be formed, and Quantum Spin Hall effect may exist. Show Chinese abstract

Abstract: 在本研究工作中，锗烯层的二维结构与二维 III 族磷化物：AlP 和 GaP 进行了复合。 AlP 和低弯曲的 GaP 的平面结构被用来形成双层结构。 在每种情况下，考虑了三种堆叠模式，并报告了其松弛后的层间距离和结合能。 结合能大约在 ~150 到 210 meV 范围内，表明层之间存在弱的范德华相互作用。 包含锗烯和这两种磷化物的异质结构显示出一个大范围的间接带隙，大小在 ~200 meV 到 600 meV 之间，可以通过改变层间距离以及引入双轴压缩和拉伸应变来调节。 尽管它们的正常带隙会随着自旋轨道耦合 (SOC) 显著变化，但仍然是间接带隙，而通过调节层间距离，带隙从不对称点跳变到对称的狄拉克锥，并在 K 点变为直接带隙。 载流子主要集中在导带区域中锗烯的 p 轨道上；因此，锗烯的电学特性将得以保留，载流子将提供更快的器件响应特性。 磷化物的影响缺失使它们成为在上面生长锗烯层的理想基底。 此外，由于狄拉克锥处的带隙被打开，并且狄拉克锥与带隙之间的跳跃随着 SOC 的变化，可以形成拓扑绝缘体，量子自旋霍尔效应可能存在。