School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
Phys Rev Lett. 2019 Oct 11;123(15):156801. doi: 10.1103/PhysRevLett.123.156801.
We propose a realization of the lattice-symmetry-assisted second-order topological superconductors with corner Majorana zero modes (MZM) based on two-dimensional topological insulators (2DTI). The lattice symmetry can naturally lead to the anisotropic coupling of edge states along different directions to the in-plane magnetic field and conventional s-wave pairings, thus leading to a single MZM located at the corners for various lattice patterns. In particular, we focus on the 2DTI with D_{3d} lattice symmetry and found different types of gap opening for the edge states along the armchair and zigzag edges in a broad range of parameters. As a consequence, a single MZM exists at the corner between the zigzag and armchair edges, and is robust against weakly broken lattice symmetry. We propose to realize such corner MZMs in a variety of polygon patterns, such as triangles and quadrilaterals. We further show their potentials in building the Majorana network through constructing the Majorana Y junction under an in-plane magnetic field.
我们提出了一种基于二维拓扑绝缘体（2DTI）的晶格对称性辅助的二阶拓扑超导体的实现方案，该方案具有角部马约拉纳零模（MZM）。晶格对称性可以自然地导致不同方向的边缘态与面内磁场和传统 s 波配对的各向异性耦合，从而导致各种晶格模式下位于角部的单个 MZM。特别是，我们关注具有 D_{3d}晶格对称性的 2DTI，并在广泛的参数范围内发现了沿扶手椅和锯齿边缘的边缘态的不同类型的能隙打开。因此，在锯齿和扶手椅边缘之间的角部存在单个 MZM，并且对弱晶格对称性的破坏具有鲁棒性。我们提出在各种多边形图案（如三角形和四边形）中实现这种角部 MZM。我们进一步通过在面内磁场下构建马约拉纳 Y 结，展示了它们在构建马约拉纳网络中的潜力。
