Study of mechanism of ferromagnetism in magnetic semiconductor and application to fabrication of magnetic nanostructure by spin-polarized STM

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K04874
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nanostructural physics
• Research Institution: University of Tsukuba
• Principal Investigator: Kanazawa Ken 筑波大学, 数理物質系, 助教 (60455920)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: スピントロニクス / 磁性半導体 / 走査プローブ顕微鏡 / 表面物理 / 分子線エピタキシー

Outline of Final Research Achievements

In this study, we performed spin-polarized-scannning tunneling microscopy (SP-STM)on transition metal atoms deposited on a (110)surface of II-VI semiconductor ZnTe, in order to clarify the spin-polarized states around the adsorbed atoms.
As results of our STM study, we found that single Cr atoms substituting into Zn sites of topmost surface of the ZnTe(110). And our STS measurements revealed Cr-induced spin-polarized impurity states in the energy gap region of the host ZnTe. 　Furthermore, by our experimental and theoretical studies, we clarified that the impurity states of the nearest-neighboring Cr atoms along the [110] direction were over rapped and imaged as a higher protrusion than that of single Cr atom reflecting the ferromagnetic interaction between them.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

本研究では、未だにその磁性の起源について未知な部分が多い磁性半導体特に(Zn,Cr)Teを対象として、スピン偏極走査トンネル顕微鏡 (SP-STM)を用いてドーパント周りの局所電子状態を調べ、磁性ドーパントにはたらく磁性相互作用の詳細を明らかにし、ボトムアップ型の新規ナノ磁気工学の構築に向けた知見を得た。さらに、今後、SP-STMにより、孤立および隣接吸着した磁性ドーパント周りの局所的なスピン偏極状態を原子スケールで観察することで、その磁気特性の起源を明らかにすることができると考えられる。