Effects of resonant interface states on tunneling magnetoresistance
Effects of resonant interface states on tunneling magnetoresistance
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DOI：
10.1103/physrevb.65.064425
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发表时间：
2002-01
影响因子：
3.7
通讯作者：
O. Wunnicke;N. Papanikolaou;R. Zeller;P. Dederichs;V. Drchal;J. Kudrnovský
中科院分区：
文献类型：
--
作者：
O. Wunnicke;N. Papanikolaou;R. Zeller;P. Dederichs;V. Drchal;J. Kudrnovský
基于模型和从头计算，我们讨论了共振界面态对外延隧道结电导的影响。特别是，我们发现的“热点”的几个小组在从头计算的对称障碍的${\mathbf{k}}_{\ensuremath{\Vert}}$-分辨电导可以解释成键和反键之间的界面态的形成的混合体两侧的障碍。如果这些混合态的共振条件得到满足，则电子隧穿势垒而没有衰减。即使当两个混合态一起移动并形成单一共振时，仍然观察到强烈增强的透射。这种效应解释了为什么对于中间势垒厚度，隧穿电导可以由界面态主导，尽管热点只发生在表面布里渊区的一小部分中。
Based on model and ab initio calculations we discuss the effect of resonant interface states on the conductance of epitaxial tunnel junctions. In particular we show that the ``hot spots'' found by several groups in ab initio calculations of symmetrical barriers of the ${\mathbf{k}}_{\ensuremath{\Vert}}$-resolved conductance can be explained by the formation of bonding and antibonding hybrids between the interface states on both sides of the barrier. If the resonance condition for these hybrid states is met, the electron tunnels through the barrier without attenuation. Even when both hybrid states move together and form a single resonance, strongly enhanced transmission is still observed. The effect explains why, for intermediate barrier thicknesses, the tunneling conductance can be dominated by interface states, although hot spots only occur in a tiny fraction of the surface Brillouin zone.