Silicon semiconductor samples implanted with Cu ions and samples co-implanted with Cu- and N-ions were prepared by MEVVA and the Kaufman technique. None of the samples showed evidence of secondary phases. The initially n-type Si matrix, when implanted with Cu ions, changed to a p-type semiconductor, and the Cu ions existed as local Cu²⁺ cations in the p-type environment. As a result, none of the Cu-implanted samples were ferromagnetic at room temperature. The co-implanted samples, on the other hand, showed room-temperature ferromagnetism because the introduction of N ions made the carrier type change from p-type to n-type which is favorable for the appearance of Cu²⁺. First principles calculations were applied to understand the experimental phenomena. The formation energy was reduced by implanting N ions, and was decreased effectively with the increase in ratio of N to Cu ions. The density of states and spin density of states indicated that the hybridization of s, p and d electrons induced ferromagnetism at 0 K. Particularly, we proposed possible exchange interactions between the Cu²⁺–N⁻(N⁴⁺)–Cu²⁺ ions to explain the ferromagnetism mechanism.

中文翻译：

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载流子类型对注入铜离子的硅半导体中铁磁性的影响

通过MEVVA和Kaufman技术制备了注入有铜离子的硅半导体样品以及共注入有铜和N离子的样品。没有样品显示出第二相的证据。最初的n型Si基体在注入Cu离子后变为p型半导体，并且Cu离子在p型环境中作为局部Cu ²⁺阳离子存在。结果，Cu注入的样品在室温下都不是铁磁性的。另一方面，共注入样品显示出室温铁磁性，因为引入N离子使载流子类型从p型变为n型，有利于Cu ²⁺的出现。。应用第一原理计算来理解实验现象。注入N离子可降低形成能，并随着N与Cu离子比的增加而有效降低。国家和国家自旋密度的密度表明，S，P和d电子诱导铁磁性的，在0 K.杂交特别是，我们提出将Cu之间的可能的交换相互作用²⁺ -N ^-（N ⁴⁺）-Cu ²⁺离子来解释铁磁性机理。