First principles studies on the geometry, electronic structure and magnetic properties of neutral, cationic, and anionic Fe₂Si_n (1≤n≤12) have been performed to better understand magnetic dopants in silicon. The doubly-Fe doped clusters in the size range 1≤n≤12 are marked by finite spin moments at the Fe sites, and Fe₂Si₃, Fe₂Si₄, and Fe₂Si₇ are found to exhibit antiferromagnetic coupling. Fe₂Si₃ and Fe₂Si₁₂ are relatively stable. We find that short Fe-Fe bond distances correlate with ferromagnetic coupling due to the destabilization of antibonding orbitals between the iron sites, while longer Fe-Fe bond distances lead to nonbonding atomic orbitals that favor antiferromagnetic coupling.

为了更好地理解硅中的磁性掺杂剂，已经对中性，阳离子和阴离子Fe ₂ Si _n（1≤n≤12）的几何形状，电子结构和磁性进行了第一性原理研究。尺寸范围为1≤n≤12的双Fe掺杂团簇在Fe处具有有限的自旋矩，并且发现Fe ₂ Si ₃，Fe ₂ Si ₄和Fe ₂ Si ₇表现出反铁磁耦合。Fe ₂ Si ₃和Fe ₂ Si ₁₂相对稳定。我们发现，由于铁位点之间反键轨道的失稳，较短的Fe-Fe键距离与铁磁耦合相关，而较长的Fe-Fe键距离会导致有利于反铁磁耦合的非键原子轨道。