Influence of the type of carrier on ferromagnetism in a Si semiconductor implanted with Cu ions. Issue 15 (1st April 2020)

• Record Type: Journal Article
• Authors: Wang, Li; Hou, Denglu; Wu, Chunfang; Shi, Yuanping; Shi, Shaohui; Gao, Weikun; Feng, Shunzhen; Liu, Yingdi; Li, Li; Ji, Denghui
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 15(2020)
• Page Start: 7759
• Page End: 7768
• Publication Date: 2020-04-01
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp05608d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Possible exchange action mechanisms to explain the ferromagnetism origin. Here, the double exchange action hopped by spin-down electron as path ① and path ②. The super exchange action hopped by spin-up electron is shown as path ③. Abstract : 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 Cu 2+ 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 Cu 2+ . 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 Cu 2+ –N − (N 4+ )–Cu 2+ ions to explain the ferromagnetism mechanism.