论文标题
Majorana Kramers对磁反应与订单两个对称性
Magnetic response of Majorana Kramers pairs with an order-two symmetry
论文作者
论文摘要
我们研究了大量电子状态的拓扑与Majorana Kramers对的磁反应，Kramers对Majorana Fermions的磁反应之间的固有关系，这是在时间反向不变的拓扑超导体的表面上。 Majoraana Kramers对施加的磁场对响应，由于时间反转和晶体对称性之间的相互作用。在本文中，我们提出了一个系统的程序，以确定具有订单两个对称性的系统中的这种表面磁反应。从与阶二二线对称性相关的拓扑不变性的分析中，可以发现磁反应分为四种类型，这归因于不同的拓扑不变性，并且表现出可区分的特征磁反应。对于由$ \ mathbb {z} _2 $拓扑不变式保护的一对kramers对，我们澄清的是，磁反应的类型仅由库珀对的fermi-surface拓扑和对称性确定。最后，我们将理论应用于Ucoge的拓扑非肌晶晶体超导状态，该状态表现出双轴各向异性磁反应。
We study an intrinsic relation between the topology of bulk electronic states and magnetic responses of Majorana Kramers pairs, Kramers pairs of Majorana fermions, on a surface of time-reversal-invariant topological superconductors. Majorana Kramers pairs respond to an applied magnetic field anisotropically due to the interplay between time-reversal and crystal symmetries. In this paper, we propose a systematic procedure to determine such surface magnetic responses in systems with an order-two symmetry. From the analysis of topological invariants associated with an order-two symmetry, it is found that magnetic responses are classified into four types, which are attributed to different topological invariants and exhibit distinguishable, characteristic magnetic responses. For a Kramers pair of Majorana fermions protected by $\mathbb{Z}_2$ topological invariants, we clarify that types of magnetic responses are determined only from Fermi--surface topology and symmetry of Cooper pairs. Finally, we apply our theory to the topological nonsymmorphic crystalline superconducting state in UCoGe, which exhibits a biaxially anisotropic magnetic response.
