Two-dimensional folding technique for enhancing Fermi surface signatures in the momentum density: Application to Compton scattering data from an Al-3 at. % Li disordered alloy
Two-dimensional folding technique for enhancing Fermi surface signatures in the momentum density: Application to Compton scattering data from an Al-3 at. % Li disordered alloy
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DOI：
10.1103/physrevb.64.045121
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发表时间：
2001-07-15
影响因子：
3.7
通讯作者：
Bansil, A
中科院分区：
文献类型：
--
作者：
Matsumoto, I;Kwiatkowska, J;Bansil, A
我们提出了一种技术，用于增强费米面（FS）签名后，在一个晶体中的三维动量密度的二维（2D）分布是在动量空间中的特定方向沿着投影。这些结果对于用高分辨康普顿散射和正电子湮没谱研究费米学是有用的。我们专注于在fcc晶体中的（110）投影的特定情况下，其中基于使用Lock-Crisp-West（LCW）折叠定理的标准方法由于与通过从较高布里渊区投影获得的FS图像的强烈重叠而未能给出清晰的FS图像。我们展示了如何使用一组选定的倒易晶格矢量在折叠过程中，这些叠加的FS图像可以解开。通过考虑Al-3原子的康普顿光谱来说明我们的部分折叠方案的适用性。% Li无序合金单晶。为此，测量了（110）面内沿沿着九个方向的高分辨率康普顿轮廓。在Al-3中相应的高精度理论分布。% Li在基于局域密度近似（LDA）的Korringa-Kohn-Rostoker相干势近似（KKR-CPA）第一性原理框架内计算。理论和实验之间的总体雅阁的一个很好的水平，尽管一些预期的差异反映电子相关效应，和部分折叠方案被示出产生一个清晰的FS图像在（110）平面在Al-3在。%的Li。
We present a technique for enhancing Fermi surface (FS) signatures in the two-dimensional (2D) distribution obtained after the 3D momentum density in a crystal is projected along a specific direction in momentum space. These results are useful for investigating fermiology via high-resolution Compton scattering and positron annihilation spectroscopies. We focus on the particular case of the (110) projection in a fcc crystal where the standard approach based on the use of the Lock-Crisp-West (LCW) folding theorem fails to give a clear FS image due to the strong overlap with FS images obtained through projection from higher Brillouin zones. We show how these superposed FS images can be disentangled by using a selected set of reciprocal lattice vectors in the folding process. The applicability of our partial folding scheme is illustrated by considering Compton spectra from an Al-3 at. % Li disordered alloy single crystal. For this purpose, high-resolution Compton profiles along nine directions in the (110) plane were measured. Corresponding highly accurate theoretical profiles in Al-3 at. % Li were computed within the local density approximation (LDA)-based Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) first-principles framework. A good level of overall accord between theory and experiment is obtained, some expected discrepancies reflecting electron correlation effects notwithstanding, and the partial folding scheme is shown to yield a clear FS image in the (110) plane in Al-3 at. % Li.