标题： 吸附原子工程超导体中的磁序：应用于反铁磁超导性 显示英文标题

标题： Adatom engineering magnetic order in superconductors: Applications to altermagnetic superconductivity

摘要： 我们从理论上研究了如何利用非常规超导体表面的吸附原子形成的超晶格来设计新型配对态，这些态破坏时间反演对称性并表现出非平凡的磁点对称性。 我们使用一个具有$d$-波超导性和次级$s$-波态的正方晶格 Hubbard 模型作为例子来说明这一点。 显示具有正方晶格对称性的吸附原子超晶格能够稳定一种“轨道反铁磁超导体”，该态表现出环形电流模式和相关的轨道磁矩，其保持超晶格平移对称性，但在四重旋转下为奇函数。 该态进一步由非零的贝里曲率四极矩表征，并且在包含自旋-轨道耦合时，由带的反铁磁自旋分裂和超晶格原胞中的非平凡自旋结构表征，其净自旋矩为零。 显示英文摘要

摘要： We study theoretically how superlattices based on adatoms on surfaces of unconventional superconductors can be used to engineer novel pairing states that break time-reversal symmetry and exhibit non-trivial magnetic point symmetries. We illustrate this using a square-lattice Hubbard model with $d$-wave superconductivity and a subleading $s$-wave state as an example. An adatom superlattice with square-lattice symmetries is shown to stabilize an "orbital-altermagnetic superconductor'', a state that exhibits loop current patterns and associated orbital magnetic moments, which preserve superlattice translations but are odd under four-fold rotations. This state is further characterized by a non-zero Berry curvature quadrupole moment and, upon including spin-orbit coupling, by an altermagnetic spin splitting of the bands and non-trivial spin textures in the superlattice unit cell, with zero net spin moment.