Local structure of Fe impurity atoms in ZnO: bulk versus surface
J. A. McLeod, D. W. Boukhvalov, D. A. Zatsepin, R. J. Green, B. Leedahl, L. Cui, E. Z. Kurmaev, I. S. Zhidkov, L. D. Finkelstein, N. V. Gavrilov, S. O. Cholakh, A. Moewes
备注：
29+ pages, 8 figures, 1 table. Accepted to J. Phys. Chem. C
By studying Fe-doped ZnO pellets and thin films with various x-ray spectroscopic techniques, and complementing this with density functional theory calculations, we find that Fe-doping in bulk ZnO induces isovalent (and isostructural) cation substitution (Fe2+ -> Zn2+). In contrast to this, Fe-doping near the surface produces both isovalent and heterovalent substitution (Fe3+ -> Zn2+). The calculations performed herein suggest that the most likely defect structure is the single or double substitution of Zn with Fe, although, if additional oxygen is available, then Fe substitution with interstitial oxygen is even more energetically favourable. Furthermore, it is found that ferromagnetic states are energetically unfavourable, and ferromagnetic ordering is likely to be realized only through the formation of a secondary phase (i.e. ZnFe2O4), or codoping with Cu.
Rapid Thermal Annealing for Surface Optimisation of ZnO Substrates for MBE-Grown Oxide Two-Dimensional Electron Gases
ZnO/ZnMgO界面二维电子气（2DEG）具有低的自旋轨道耦合和高的电子迁移率，在自旋电子学和量子计算中具有广阔的应用前景。生长高迁移率2DEG需要具有低杂质密度的高质量衬底。在这项工作中，我们展示了ZnO衬底样品处理结合高温快速热退火和化学蚀刻，以提高后续的2DEG生长的表面质量。该工艺能够生长低温迁移率为$4.8\times10^4$ ~cm $^2$ V $^{-1}$ s $^{-1}$的2DEG。未退火的对照样品显示出比退火样品大至少三倍的散射率。
Strain glass versus antisite disorder induced ferromagnetic state in Fe doped Ni-Mn-In Heusler martensites
Fe掺杂在Ni $_2$ Mn $_{1.5}$ In $_{0.5}$中通过两种相反的途径导致马氏体相的抑制。在Ni $_2$ Mn $_{1.5-x}$ Fe $_{0.5}$中，马氏体相转化为应变玻璃相，而在Ni $_{2-y}$ Fe $_y$ Mn $_{0.5}$中，以马氏体为代价产生立方铁磁相。仔细的磁性和结构性质的研究揭示了杂质$γ-$（Fe，Ni）相的存在作为非遍历应变玻璃相的出现的原因，当Fe试图被掺杂在X $_2$ YZ Heusler合金的Y/Z（Mn）位置。而试图在X（Ni）亚晶格中掺杂Fe导致A2型反位无序，促进铁磁基态。
Accelerated Dopant Screening in Oxide Semiconductors via Multi-Fidelity Contextual Bandits and a Three-Tier DFT Validation Funnel
National Institute of Electronics and Information Technology (NIELIT), India（印度国家电子与信息技术研究院（NIELIT））；Indian Institute of Information Technology, Allahabad (IIITA), Prayagraj, India（印度阿拉哈巴德信息技术学院（IIITA），普拉亚格拉杰，印度）
