Ezawa Motohiko
Department of Applied Physics, University of Tokyo, Hongo 7-3-1, 113-8656, Japan.
Phys Rev Lett. 2015 Feb 6;114(5):056403. doi: 10.1103/PhysRevLett.114.056403. Epub 2015 Feb 5.
We investigate the realization of a topological superconductor in a generic bucked honeycomb system equipped with four types of mass-generating terms, where the superconductor gap is introduced by attaching the honeycomb system to an s-wave superconductor. Constructing the topological phase diagram, we show that Majorana modes are formed in the phase boundary. In particular, we analyze the honeycomb system with antiferromagnetic order in the presence of perpendicular electric field E(z). It becomes topological for |E(z)|>E(z)(cr) and trivial for |E(z)|<E(z)(cr), with E(z)(cr) a certain critical field. It is possible to create a topological spot in a trivial superconductor by controlling applied electric field. One Majorana zero-energy bound state appears at the phase boundary. We can arbitrarily control the position of the Majorana fermion by moving the spot of applied electric field, which will be made possible by a scanning tunneling microscope probe.
我们研究了在配备四种类型质量生成项的一般弯曲蜂窝系统中拓扑超导体的实现情况，其中通过将蜂窝系统与s波超导体相连引入超导能隙。构建拓扑相图时，我们表明马约拉纳模式在相边界处形成。特别地，我们分析了在垂直电场E(z)存在下具有反铁磁序的蜂窝系统。当|E(z)|>E(z)(cr)时它变为拓扑的，而当|E(z)|<E(z)(cr)时变为平凡的，其中E(z)(cr)是某个临界场。通过控制外加电场，可以在平凡超导体中创建一个拓扑点。在相边界处会出现一个马约拉纳零能束缚态。我们可以通过移动外加电场的点来任意控制马约拉纳费米子的位置，这将通过扫描隧道显微镜探针得以实现。
