Self-organized topological state in a magnetic chain on the surface of a superconductor
Self-organized topological state in a magnetic chain on the surface of a superconductor
复制标题
DOI：
10.1103/physrevb.90.085124
复制
发表时间：
2014-06
影响因子：
3.7
通讯作者：
I. Reis;D. Marchand;M. Franz
中科院分区：
文献类型：
--
作者：
I. Reis;D. Marchand;M. Franz
与普通s波超导体表面的磁性原子链相关的电子态在理论上已被证明可以形成一个一维拓扑相，未配对的马约拉纳费米子束缚在其两端。在一个简单的一维有效模型中，该系统表现出一种有趣的自组织特性：由原子磁矩形成的螺旋的螺距倾向于自我调整，以便电子链保持在拓扑相中，无论这种状态在物理上是可访问的。在这里，我们在一个更现实的二维超导表面模型的框架下，研究了这种自组织特性的物理基础，该模型耦合到磁性原子的一维链。对超导序和磁矩进行自一致处理，我们发现系统保持了自组织性质，即使拓扑相在相图中延伸的部分比一维模型要小一些。我们还研究了缺陷的影响，并发现，一旦建立，拓扑相存活适度水平的无序。
Electronic states associated with a chain of magnetic adatoms on the surface of an ordinary s- wave superconductor have been shown theoretically to form a one dimensional topological phase with unpaired Majorana fermions bound to its ends. In a simple 1D effective model the system exhibits an interesting self-organization property: the pitch of the spiral formed by the adatom magnetic moments tends to adjust itself so that electronically the chain remains in the topological phase whenever such a state is physically accessible. Here we examine the physics underlying this self-organization property in the framework of a more realistic 2D model of a superconducting surface coupled to a 1D chain of magnetic adatoms. Treating both the superconducting order and the magnetic moments selfconsistently we find that the system retains its self-organization property, even if the topological phase extends over a somewhat smaller portion of the phase diagram compared to the 1D model. We also study the effect of imperfections and find that, once established, the topological phase survives moderate levels of disorder.