发表机构
I. Institut für Theoretische Physik, Universität Hamburg（汉堡大学理论物理第一研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究探讨掺杂反铁磁体中长程尼尔序丧失后，反铁磁弦机制如何转变为由半涡旋对数禁闭的二维拓扑纹理，揭示禁闭仍存在但机制改变。
AI 中文摘要
早期对掺杂反铁磁体的弦描述将局部尼尔有序背景中的空穴运动与路径依赖的反铁磁弦联系起来。我们探讨当长程尼尔序丧失而短程反铁磁关联持续存在时，这一机制会变成什么。长程序的丧失使得投影RP^2描述成为可能，并开启了一个新的拓扑非平凡扇区。其基本缺陷是线性稳定的半涡旋，一对具有相反绕数的半涡旋受到对数禁闭，V(R) = κ ln (R/r_core)，κ = πρ_s /2。由此产生的禁闭不是由一维弦承载，而是由扩展的二维自旋纹理承载。因此，长程尼尔序的丧失并未消除反铁磁禁闭，而是开启了一种不同的投影机制，在该机制中，局部的路径依赖弦在长波长下被具有对数禁闭的全局拓扑纹理所取代。
英文摘要
Early string descriptions of doped antiferromagnets associate hole motion in a locally Néel ordered background with a path dependent antiferromagnetic string. We ask what becomes of this mechanism when long range Neel order is lost while short range antiferromagnetic correlations persist. The loss of long range order makes the projective RP^2 description admissible and opens a new topologically nontrivial sector. Its elementary defects are half vortices that globally minimize the RP^2 sigma-model energy within the nontrivial Z_2 sector. An a posteriori energetic comparison further shows why, once accessible, the projective director sector is favored over the corresponding vector reference texture. A pair of half vortices with opposite windings is logarithmically confined, V(R) = κ\ln\left(R/r_{\text{core}}\right), κ= πρ_s /2. The resulting confinement is carried not by a one dimensional string but by an extended two dimensional spin texture. Thus, the loss of long range Néel order does not eliminate antiferromagnetic confinement but opens a distinct projective mechanism in which a local path dependent string is replaced, at long wavelengths, by a global topological texture with logarithmic confinement.
CommentsVersion 2: global stability proof added; director RP^2 target space justified a posteriori by energetic comparison. Main conclusions unchanged
