Influence of lattice effects on the electron-positron interaction in metals.
Influence of lattice effects on the electron-positron interaction in metals.
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晶格效应对金属中电子-正电子相互作用的影响。
DOI：
10.1103/physrevb.54.4558
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Sormann
中科院分区：
文献类型：
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作者：
Sormann
我们通过使用布洛赫修正阶梯（BML）理论的替代版本（我们称之为优化的 BML 近似）来描述晶格对金属中电子-正电子湮灭率增强的影响。这种解决正电子与不均匀电子气相互作用的问题的方法可以可靠地应用于具有高和中价电子密度的金属，尤其是过渡金属，但对于具有低电子密度的金属例如碱金属来说效率较低。它使我们能够以近似但物理上合理的方式描述晶格效应的作用。该论文提供了 (i) 理论的广泛介绍和 (ii) 对一系列简单金属和 d 带金属（Al、Cu、Pd、Mn 和 V）在中心动量区域和近 umklapp 区域获得的动量相关增强结果的总结。将这些 BML 增强因子与局部密度近似的相应结果以及从二维角度相关实验中提取的增强因子进行比较。本文的主要结果是，我们能够证明，对于所有金属和所研究的动量空间的所有区域，电子-正电子增强的晶格效应是显着的，因此在理论工作中不应被忽视。© 1996 美国物理学会。
We describe the influence of the crystal lattice on the enhancement of the electron-positron annihilation rate in metals by the use of an alternative version of the Bloch-modified ladder (BML) theory, which we call the optimized BML approximation. This approach to the problem of positrons interacting with an inhomogeneous electron gas can be reliably applied to metals with high and medium valence electron density, especially to transition metals, but is less efficient for metals with low electron densities such as, eg, alkali metals. It enables us to describe the role of lattice effects in an approximative but nevertheless physically reasonable way. The paper offers (i) an extensive presentation of the theory and (ii) a summary of momentum-dependent enhancement results obtained for a series of simple and d-band metals (Al, Cu, Pd, Mn, and V) both for the central momentum region and for near umklapp regions. These BML enhancement factors are compared with corresponding results of the local-density approximation and with enhancement factors extracted from two-dimensional angular correlation experiments. The main result of this paper is that we are able to demonstrate that for all metals and for all regions of the momentum space investigated, the lattice effects on the electron-positron enhancement are significant and therefore should not be neglected in theoretical work.© 1996 The American Physical Society.