Spinodal nanodecomposition in semiconductors doped with transition metals
Spinodal nanodecomposition in semiconductors doped with transition metals
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DOI：
10.1103/revmodphys.87.1311
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发表时间：
2015-11-19
影响因子：
44.1
通讯作者：
Katayama-Yoshida, H.
中科院分区：
文献类型：
--
作者：
Dietl, T.;Sato, K.;Katayama-Yoshida, H.
本综述介绍了自旋电子材料（例如磁掺杂半导体）中三维和二维晶体生长条件下旋节线纳米分解的计算材料设计、实验实现和控制方法的最新进展。通过将第一原理计算与动力学蒙特卡罗模拟相结合来进行纳米分解的计算描述，并与广泛的电子显微镜、同步加速器辐射、扫描探针和离子束方法一起讨论，这些方法已用于可视化一系列过渡金属 (TM) 杂质浓度超出溶解度极限的半导体化合物中的双节和旋节纳米分解（化学相分离）以及纳米沉淀（晶体相分离）。强调了生长条件、浅层杂质共掺杂、动力学势垒和表面反应在控制磁性阳离子聚集中的作用。根据理论模拟和实验结果，富含 TM 的区域以纳米点（daiiseki 相）或纳米柱（昆布相）的形式埋在主体半导体中。特别关注Mn掺杂的III族砷化物和锑化物、TM掺杂的III族氮化物、Mn和Fe掺杂的Ge以及Cr掺杂的II族硫属化物，其中在室温以上持续存在的铁磁特征与纳米分解的存在相关，并解释了这些化合物与应用相关的磁光和磁输运性质。最后，指出旋节线纳米分解可以被视为一类新的自下而上的纳米制造方法。
This review presents the recent progress in computational materials design, experimental realization, and control methods of spinodal nanodecomposition under three- and two-dimensional crystal-growth conditions in spintronic materials, such as magnetically doped semiconductors. The computational description of nanodecomposition, performed by combining first-principles calculations with kinetic Monte Carlo simulations, is discussed together with extensive electron microscopy, synchrotron radiation, scanning probe, and ion beam methods that have been employed to visualize binodal and spinodal nanodecomposition (chemical phase separation) as well as nanoprecipitation (crystallographic phase separation) in a range of semiconductor compounds with a concentration of transition metal (TM) impurities beyond the solubility limit. The role of growth conditions, codoping by shallow impurities, kinetic barriers, and surface reactions in controlling the aggregation of magnetic cations is highlighted. According to theoretical simulations and experimental results the TM-rich regions appear in the form of either nanodots (the dairiseki phase) or nanocolumns (the konbu phase) buried in the host semiconductor. Particular attention is paid to Mn-doped group III arsenides and antimonides, TM-doped group III nitrides, Mn- and Fe-doped Ge, and Cr-doped group II chalcogenides, in which ferromagnetic features persisting up to above room temperature correlate with the presence of nanodecomposition and account for the application-relevant magneto-optical and magnetotransport properties of these compounds. Finally, it is pointed out that spinodal nanodecomposition can be viewed as a new class of bottom-up approach to nanofabrication.