AI 中文总结
本文提出场控纳米接触协议，通过微磁模拟实现嵌套斯格明子袋的区域选择性写入与编程，为多级自旋电子信息编码提供了可行途径。
AI 中文摘要
嵌套斯格明子袋是复合磁孤子，其内部占据数为多级信息编码提供了扩展的状态空间。然而，将单个斯格明子确定性且区域选择性地写入嵌套斯格明子袋仍然具有挑战性。本文利用微磁模拟，提出一种场控纳米接触协议，用于生成和编程双层嵌套斯格明子袋S(m,S(n))。该协议利用具有反平行磁背景的袋区域的相反场响应，空间分段的垂直磁场可选择性地扩展外层区域或内部袋，直至其与纳米接触重叠。随后，适当极性的自旋极化电流脉冲在选定区域成核一个斯格明子，之后的场驱动收缩将写入的斯格明子移离接触点，并恢复写入位点以重复操作。从空嵌套斯格明子袋S(0,S(0))开始，该流程可实现S(m,S(0))、S(0,S(n))及通用S(m,S(n))态的可控构建。模拟中，连续写入过程的总拓扑荷以单位步长变化，证实了单次且区域选择性的控制。这些结果为多级自旋电子信息编码的可编程嵌套拓扑态提供了可行途径。
英文摘要
Nested skyrmion bags are composite magnetic solitons whose internal occupation numbers provide an expanded state space for multilevel information encoding. However, deterministic and region-selective writing of individual skyrmions into nested bags remains challenging. Here, using micromagnetic simulations, we propose a field-gated nanocontact protocol for generating and programming double-layer nested skyrmion bags S(m,S(n)). The protocol exploits the opposite field responses of bag regions with antiparallel magnetic backgrounds. Spatially segmented perpendicular magnetic fields selectively expand either the outer region or the inner bag until it overlaps with a nanocontact. A spin-polarized current pulse of the appropriate polarity then nucleates one skyrmion in the selected region, while subsequent field-driven contraction moves the written skyrmion away from the contact and restores the writing site for repeated operation. Starting from an empty nested bag S(0,S(0)), this procedure enables the controlled construction of S(m,S(0)), S(0,S(n)), and general S(m,S(n)) states. The simulated total topological charge changes in unit steps during sequential writing, confirming one-at-a-time and region-selective control. These results provide a possible route toward programmable nested topological states for multilevel spintronic information encoding.
