AI 中文总结
本文通过理论与模拟，提出利用碎片化自旋冰的畴壁设计单极子二极管、电容器及电池，为控制磁流及研究准粒子跨畴壁动力学提供了新方向。
AI 中文摘要
自旋冰材料以类磁单极子的准粒子激发闻名，磁流（magnetricity）概念认为这些单极子可传导交流磁电流，类似传导电子。尽管单极子动力学已被深入研究且理解较充分，但设计控制磁流的器件却鲜有进展。本文针对单极子输运的二极管与电容器设计，开展理论概念验证，利用自旋冰物理与长程反铁磁序共存的磁碎片化系统特性，关键在于磁序可产生畴壁；在特定制备条件下，该畴壁等效于单极子的非对称滤波器：某一方向正电荷可通过而负电荷被排斥，反向则相反，此不对称性有效构成单极子电流的二极管；连续畴壁分隔正负电荷，中间形成电荷真空，构成单极子电容器，充电后原则上可作为单极子电池。本文解释了所有微观机制，通过超过100万自旋的模拟验证了概念，讨论了其在稀土烧绿石氧化物和人工自旋冰实验中的应用，还指出碎片化自旋冰中的畴壁可视为分离时间反演对称的两个镜像“世界”的涌现边界，本研究为手性和向列自旋液体中涌现准粒子跨畴壁动力学开辟了有前景的研究方向。
英文摘要
Spin-ice materials are famous for their quasi-particle excitations that behave like magnetic monopoles. Magnetricity is the concept that these monopoles can conduct an AC magnetic current, in analogy with conduction electrons. While monopole dynamics has been intensively studied and is reasonably well understood, very little has been done to design devices in order to control magnetricity. Here we develop a theoretical proof of concept for the design of diodes and capacitors for the transport of monopoles. We use the property of systems with magnetic fragmentation, where spin-ice physics co-exists with long-range antiferromagnetic order. The key point is that magnetic order allows for the existence of domain walls. Under certain conditions of preparation, this domain wall is equivalent to an asymmetric filter for monopoles. In a given direction, positive charges can go through while negative ones are repelled; the opposite applies in the opposite direction. This asymmetry effectively functions like a diode for monopole current. Successive domain walls separate positive from negative charges with a vacuum of charge in between, producing a capacitor for monopoles. Once the capacitor is charged, it can in principle be used as a battery for monopoles. All microscopic mechanisms are explained and our proof of concept is validated by simulations of more than a million spins. Application to experiments are discussed for rare-earth pyrochlore oxides and artificial spin ice. Finally, we discuss in general terms how a domain wall in fragmented spin ice can also be seen as an emergent boundary separating two mirror "worlds" separated by time-reversal symmetry. Beyond spin ice, our work opens a promising direction of investigation for the dynamics of emergent quasi-particles crossing domain walls in chiral and nematic spin liquids, which also possess a broken symmetry.
