论文标题
$ {\ Mathcal P} $ - ，$ {\ MATHCAL T} $的高阶拓扑超导体
Higher-order topological superconductors in ${\mathcal P}$-, ${\mathcal T}$-odd quadrupolar Dirac materials
论文作者
论文摘要
正常状态（NS）中某些对称性的存在也决定了库珀对的对称性。 Here we show that parity (${\mathcal P}$) and time-reversal (${\mathcal T}$) odd Dirac insulators (trivial or topological) or metals, sustain a local or intra-unit cell pairing that supports corner (in $d=2$) or hinge (in $d=3$) modes of Majorana fermions and stands as a higher-order topological superconductor （HOTSC），当NS另外打破离散的四倍（$ C_4 $）对称性时。尽管这些结果并不依赖于费米表面的存在，但周围（当系统被掺杂时）hotsc采取了混合均等的形式，$ {\ nathcal t} $ - 奇数（由于缺乏$ {\ nathcal p} $ {\ nathcal p} $和$ {\ nathcal t} $ ns $ p+p+d werve $ p+d p y id d d p y ns $ p p y des $ p。源自NS中准颗粒的狄拉克（Dirac）性质（缺乏$ c_4 $对称性）。因此，当紧张时，磁性有序的零材料（例如掺杂的磁性拓扑造型器（MNBI $ _2 $ te $ _4 $））可以携带HotScs，而缺乏外部应变应有助于轴支$ P+P+是$ $是$配对。
The presence or absence of certain symmetries in the normal state (NS) also determines the symmetry of the Cooper pairs. Here we show that parity (${\mathcal P}$) and time-reversal (${\mathcal T}$) odd Dirac insulators (trivial or topological) or metals, sustain a local or intra-unit cell pairing that supports corner (in $d=2$) or hinge (in $d=3$) modes of Majorana fermions and stands as a higher-order topological superconductor (HOTSC), when the NS additionally breaks discrete four-fold ($C_4$) symmetry. Although these outcomes does not rely on the existence of a Fermi surface, around it (when the system is doped) the HOTSC takes the form of a mixed parity, ${\mathcal T}$-odd (due to the lack of ${\mathcal P}$ and ${\mathcal T}$ in the NS, respectively) $p+id$ pairing, where the $p$($d$)-wave component stems from the Dirac nature of quasiparticles (lack of $C_4$ symmetry) in the NS. Thus, when strained, magnetically ordered Dirac materials, such as doped magnetic topological insulators (MnBi$_2$Te$_4$), can harbor HOTSCs, while the absence of an external strain should be conducive for the axionic $p+is$ pairing.
