论文标题
超导时间反转对称的Weyl半度法的Fermi Arc标准
Fermi arc criterion for surface Majorana modes in superconducting time-reversal symmetric Weyl semimetals
论文作者
论文摘要
通过利用金属和绝缘体中超导性与带拓扑之间的相互作用，已经发现了许多通往Majorana Fermions的巧妙路线。但是，半学的实现仍然不那么探索。我们问，``在时间反转对称的Weyl半学分中超导涡旋 - 只有时间反转对称性的三维半学 - 在表面上捕获大元素的fermana fermions？''''如果每个常数？涡流并在费米弧结构方面得出拓扑不变的$ν= \ pm1 $，该结构标志着存在或不存在表面majorana fermions。相比之下，如果某些常量为$ k_ {z} $ planes包含Weyl节点的净手性，则涡流是无间隙的。我们在扰动方案中分析计算$ν$，并通过晶格模型提供数值支持。该标准在倾斜涡流时在琐碎，无间隙和拓扑涡流之间存在其他散装带和表面带的存在以及产量相变。我们提出Li（Fe $ _ {0.91} $ CO $ _ {0.09} $）和Fe $ _ {1+y} $ se $ _ {0.45} $ _ {0.45} $ te $ _ {0.55} $，损坏的反转对称性作为候选人来实现我们的建议。
Many clever routes to Majorana fermions have been discovered by exploiting the interplay between superconductivity and band topology in metals and insulators. However, realizations in semimetals remain less explored. We ask, ``under what conditions do superconductor vortices in time-reversal symmetric Weyl semimetals -- three-dimensional semimetals with only time-reversal symmetry -- trap Majorana fermions on the surface?'' If each constant-$k_{z}$ plane, where $z$ is the vortex axis, contains equal numbers of Weyl nodes of each chirality, we predict a generically gapped vortex and derive a topological invariant $ν=\pm1$ in terms of the Fermi arc structure that signals the presence or absence of surface Majorana fermions. In contrast, if certain constant-$k_{z}$ planes contain a net chirality of Weyl nodes, the vortex is gapless. We analytically calculate $ν$ within a perturbative scheme and provide numerical support with a lattice model. The criteria survive the presence of other bulk and surface bands and yield phase transitions between trivial, gapless and topological vortices upon tilting the vortex. We propose Li(Fe$_{0.91}$Co$_{0.09}$)As and Fe$_{1+y}$Se$_{0.45}$Te$_{0.55}$ with broken inversion symmetry as candidates for realizing our proposals.
