磁性原子链中的拓扑超导相竞争  

Topological superconducting phase competition in magnetic atomic rings

作　　者：崔娜玮 高嘉忻 董慧薷 李传奇 罗小兵 肖进鹏 Cui Na-Wei;Gao Jia-Xin;Dong Hui-Ru;Li Chuan-Qi;Luo Xiao-Bing;Xiao Jin-Peng(School of Mathematics and Physics,Jinggangshan University,Ji’an 343009,China;Zhejiang Sci-Tech University,Hangzhou 310018,China)

机构地区：[1]井冈山大学数理学院,吉安343009 [2]浙江理工大学,杭州310018

出　　处：《物理学报》2024年第23期184-191,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11947082,12375022,11975110);江西省教育厅科技计划(批准号:GJJ190577)资助的课题.

摘　　要：穿过磁性原子环的磁通能够诱导拓扑超导,这种方法既不需要自旋轨道耦合也不需要螺旋磁序,为实现低维拓扑超导提供新的思路.本文介绍了在二维s波超导表面环状沉积铁磁序磁性原子链模型,阐述了在此模型中磁通诱导拓扑超导的原理.同时考虑实际实验,磁性原子链打破了二维衬底表面的空间反演对称性,带来了Rashba自旋轨道耦合,进而导致原子链螺旋磁序的出现.研究了Rashba自旋轨道耦合和螺旋磁序对拓扑超导态的影响.结果发现,自旋轨道耦合对原有拓扑态具有破坏性的影响,而螺旋磁序只是推动了相变点在参数空间的转移,不破坏原有拓扑态.A magnetic flux threading through magnetic atomic rings can induce topological superconductivity.It provides a novel approach to achieving low-dimensional(2D)topological superconductivity,which requires neither spin-orbit coupling nor helical magnetic order.In this paper,we introduce a topological superconductor model by depositing a ferromagnetic atomic ring on the surface of a 2D s-wave superconductor.When the moments of the magnetic atoms are perpendicular to the external magnetic field,a magnetic flux can induce topological superconductivity.Considering practical experiments,because the magnetic atomic chain breaks the inversion symmetry of the surface of the 2D substrate,the Rashba spin-orbit coupling(SOC)is introduced,leading to the appearance of helical magnetic order in the atomic chain.According to previous researches,this helical magnetic order ensures that the magnetic moments of the ring are perpendicular to the external magnetic field,and the patch angle of neighbor moment of the helical order is proportional to the strength of the SOC.However,the helical order or Rashba SOC may introduce topological superconductivity on their own.It is meaningful to investigate the influence of the effects of the Rashba SOC and helical magnetic order on the flux induced topological superconducting states.We find that the Rashba SOC has a disruptive effect on the existing topological state,while helical magnetic order merely shifts its transition position in the parameter space.Therefore,when selecting materials for experiment,it is recommended to choose materials with lower Rashba SOC strength.

关 键 词：拓扑超导 磁性原子环 铁磁序 

分 类 号：O469[理学—凝聚态物理]