Spin injection at heusler/semiconductor interfaces: First-principles determination of potential discontinuity and half-metallicity
Spin injection at heusler/semiconductor interfaces: First-principles determination of potential discontinuity and half-metallicity
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DOI：
10.1063/1.1608469
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发表时间：
2003-09
影响因子：
3.2
通讯作者：
S. Picozzi;A. Continenza;A. Freeman
中科院分区：
文献类型：
--
作者：
S. Picozzi;A. Continenza;A. Freeman
通过对Co2MnGe/GaAs和Co2MnGe/Ge界面的精确第一性原理方法，确定了技术相关属性，如潜在的不连续和半金属行为。界面态出现在结的两侧，因此半金属性，典型的大块Co2MnGe，局部丢失。对于电势不连续，接触特性受到半导体侧的显著影响：在Co2MnGe/GaAs中，无论原子末端如何，费米能级都被固定在能带间隙内，而在Co2MnGe/Ge的情况下，费米能级接近价带最大值。这在第一种情况下产生整流接触，在第二种情况下产生孔洞的欧姆，两者都可能用于自旋注入目的。最后，我们研究了大块Co2MnGe中可能的Co-Mn反位的影响，发现半金属性仅在局部被破坏，因为缺陷引起的间隙态被显示在几个最近邻的原子中被屏蔽。
Technologically relevant properties, such as potential discontinuity and half-metallic behavior, are determined by means of an accurate first-principles approach for Co2MnGe/GaAs and Co2MnGe/Ge interfaces. Interface states appear in both sides of the junctions, so that half-metallicity, typical of bulk Co2MnGe, is locally lost. As for the potential discontinuity, the character of the contact is dramatically affected by the semiconductor side: In Co2MnGe/GaAs, irrespective of the atomic termination, the Fermi level is pinned within the energy band gap, whereas it lies close to the valence-band maximum in the case of Co2MnGe/Ge. This gives rise to a rectifying contact in the first case and ohmic for holes in the second case, both potentially useful for spin–injection purposes. Finally, we investigate the effects of possible Co–Mn antisites in bulk Co2MnGe and find that half-metallicity is only locally destroyed, since defect-induced gap states are shown to be screened in a couple of nearest-neighbor atomic ...