Crossover from spin accumulation into interface states to spin injection in the germanium conduction band
A. Jain, J. -C. Rojas-Sanchez, M. Cubukcu, J. Peiro, J. C. Le Breton, E. Prestat, C. Vergnaud, L. Louahadj, C. Portemont, C. Ducruet, V. Baltz, A. Barski, P. Ba… 展开作者
A. Jain, J. -C. Rojas-Sanchez, M. Cubukcu, J. Peiro, J. C. Le Breton, E. Prestat, C. Vergnaud, L. Louahadj, C. Portemont, C. Ducruet, V. Baltz, A. Barski, P. Bayle-Guillemaud, L. Vila, J. -P. Attané, E. Augendre, G. Desfonds, S. Gambarelli, H. Jaffrès, J. -M. George, M. Jamet
Electrical spin injection into semiconductors paves the way for exploring new phenomena in the area of spin physics and new generations of spintronic devices. However the exact role of interface states in spin injection mechanism from a magnetic tunnel junction into a semiconductor is still under debate. In this letter, we demonstrate a clear transition from spin accumulation into interface states to spin injection in the conduction band of $n$-Ge. We observe spin signal amplification at low temperature due to spin accumulation into interface states followed by a clear transition towards spin injection in the conduction band from 200 K up to room temperature. In this regime, the spin signal is reduced down to a value compatible with spin diffusion model. More interestingly, we demonstrate in this regime a significant modulation of the spin signal by spin pumping generated by ferromagnetic resonance and also by applying a back-gate voltage which are clear manifestations of spin current and accumulation in the germanium conduction band.
Ferromagnetism and Metamagnetism in Copper-doped Germanium Clathrate
铜掺杂的I型锗笼形物在90 K以下表现出弱磁性，包括铁磁性、反铁磁性和变磁转变。63 Cu NMR测量证实，这些转变是由于通过传导电子耦合的磁性缺陷的稀组合物，行为类似于磁性半导体。磁性测量表明局部的磁矩，归因于磁性离子簇，铁磁和反铁磁交换之间的竞争，也表明在铁磁相的玻璃态行为。核磁共振奈特位移和弛豫时间表明，导带是金属与一个大的科林加比。与平均场论的有序行为的比较给出了一个很好的解释铁磁转变。
Electrical spin injection and detection in Germanium using three terminal geometry
在这封信中，我们报告成功的电自旋注入和检测\textit{n}型绝缘体上锗（GOI）使用Co/Py/Al $_{2}$ O $_{3}$自旋注入器和3端非本地测量。我们观察到一个增强的自旋积累信号的顺序为1毫电子伏的顺序隧穿过程通过界面状态附近的Al $_{2}$ O $_{3}$ /Ge接口。该自旋信号在高达220 K时可进一步观察到。此外，强的\textit{inverted} Hanle效应的存在表明，注入自旋受到界面粗糙度引起的随机场的影响。
An accurate alternative to hybrid functionals for germanium: DFT+$α$
SISSA–Scuola Internazionale Superiore di Studi Avanzati（的里雅斯特高等国际研究学院）；AREA Science Park（AREA科学园）；CNR-Istituto Officina dei Materiali (IOM)（意大利国家研究委员会材料研究所）；CEA, DAM, DIF（法国原子能和替代能源委员会）
Magnetotransport in Bi$_2$Se$_3$ thin films epitaxially grown on Ge(111)
像Bi $_2$ Se $_3$的拓扑绝缘体（TI）是一类具有拓扑保护的表面态的材料，其中自旋-动量锁定可以实现自旋极化和缺陷容限传输。在本工作中，我们实现了在微电子关键材料锗上外延生长Bi $_2$ Se $_3$薄膜。锗还表现出关于电子自旋的有趣性质，例如在室温下几微米的自旋扩散长度。通过在锗上生长Bi $_2$ Se $_3$，我们旨在将Ge的长自旋扩散长度与Bi $_2$ Se $_3$表面的自旋-动量锁定结合起来。我们首先进行了彻底的结构分析的Bi $_2$ Se $_3$薄膜，使用电子和X射线衍射以及原子力显微镜。然后，在低温下的磁输运测量表明，由于二维运输的拓扑保护的表面状态的Bi $_2$ Se $_3$的签名弱反本地化。有趣的是，磁输运测量还指出，导电沟道可以通过偏置电压或施加的磁场在Bi $_2$ Se $_3$膜和下面的Ge层之间调谐。这一结果表明，Bi $_2$ Se $_3$ /Ge结是一个很有前途的候选人，用于调谐在TI和半导体之间的界面处的自旋相关现象。
