发表机构
Rose-Hulman Institute of Technology（罗斯-赫尔曼理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过密度泛函理论揭示，在单层六方氮化硼中，空位对的原子尺度位置可反转其自旋排列偏好，为调控耦合自旋中心提供微观基础。
AI 中文摘要
带负电的硼空位是六方氮化硼（hBN）中一种光学可寻址的自旋中心，但将两个空位放在一起会引入孤立缺陷图像中不存在的电子相互作用。这里我们使用总电荷 q = -2 的密度泛函理论表明，原子尺度的位点放置反转了单层 hBN 中优选的共线自旋排列。在七种构型中，最近的一对空位，间距为 4.3 埃，在半导体局域近似下偏好平行排列，能量差为 27.6 meV。将一个空位移动单个晶格矢量会反转这一偏好，而间距为 7.5 埃的一对空位则偏好反平行排列，能量差为 50.7 meV。数值控制使这两个参考分裂改变小于 1 meV；混合泛函计算保留其符号，但显著改变其大小。局域畸变将 7.5 埃处的反平行偏好与沿中间原子链的空位态杂化变化联系起来。最近的一对反而表现出接触局域的自旋密度对比和受约束的角度能量，偏离双线性海森堡形式。这些结果识别出一个对位点敏感的相互作用缺陷区域，并为研究原子薄材料中耦合自旋中心提供了微观基础。
英文摘要
The negatively charged boron vacancy is an optically addressable spin centre in hexagonal boron nitride (hBN), but bringing two vacancies together introduces electronic interactions absent from the isolated-defect picture. Here we use density-functional theory at total charge q = -2 to show that atomic-scale placement reverses the preferred collinear spin alignment in monolayer hBN. Among seven configurations, the closest pair, separated by 4.3 angstrom, favours parallel alignment by 27.6 meV within the semilocal approximation. Moving one vacancy by a single lattice vector reverses the preference, and a 7.5 angstrom pair favours antiparallel alignment by 50.7 meV. Numerical controls change these two reference splittings by less than 1 meV; hybrid-functional calculations retain their signs while substantially changing their magnitudes. Local distortions connect the antiparallel preference at 7.5 angstrom to changes in vacancy-state hybridization along an intervening atomic chain. The closest pair instead exhibits a contact-localized spin-density contrast and constrained angular energies that depart from the bilinear Heisenberg form. These results identify a placement-sensitive regime of interacting defects and provide a microscopic foundation for investigating coupled spin centres in atomically thin materials.
Comments15-page main text, 4 main figures; 72-page Supplementary Information included in the same PDF
