Electronic structure of quasicrystalline surfaces: Effects of surface preparation and bulk structure
Electronic structure of quasicrystalline surfaces: Effects of surface preparation and bulk structure
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准晶表面的电子结构：表面处理和体结构的影响
DOI：
10.1103/physrevb.62.14049
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发表时间：
2000
影响因子：
3.7
通讯作者：
P. Thiel
中科院分区：
文献类型：
--
作者：
V. Fournée;P. Pinhero;J. Anderegg;T. Lograsso;A. R. Ross;P. Canfield;I. Fisher;P. Thiel
我们阐明了准晶Al-Pd-Mn表面电子性质的本质。我们通过使用光电子和俄歇电子能谱，并通过各种比较-跨类型的散装样品，跨方法的表面制备。主要结论是：（1）在二十面体相中观察到的窄Mn 2 p {sub 3/2}芯能级线是费米能级处态密度抑制（赝能隙）的指纹，而不是准晶相所特有的。它也与准晶表面的对称性无关。俄歇线的形状也受到影响，可以用作伪间隙的指纹。(ii)一个类似的窄Fe 2 p {sub 3/2}核心水平线的二十面体的Al-Cu-Fe准晶的特点，符合预期的电子结构是一般的重要性，在二十面体相的稳定。(iii)在二十面体Al-Pd-Mn中，本体的赝隙在断裂后立即不保留到表面，但可以通过退火或通过溅射退火到足够高的温度来恢复。假设赝能隙反映了原子结构的电子稳定性，这些结果表明热处理表面比通过在室温下破裂获得的表面更稳定。«少
We elucidate the nature of the surface electronic properties of quasicrystalline Al-Pd-Mn. We do this by using photoelectron and Auger electron spectroscopies, and by making a variety of comparisons -- across types of bulk samples, and across methods of surface preparation. The main conclusions are these: (i) The narrow Mn 2p{sub 3/2} core-level line observed in the icosahedral phase is a fingerprint of a suppression in the density of states (a pseudogap) at the Fermi level and is not unique to the quasicrystalline phase. It is also independent of the symmetry of the quasicrystalline surface. The Auger line shape is also affected and may be used as a fingerprint of a pseudogap. (ii) A similarly narrow Fe 2p{sub 3/2} core-level line characterizes the icosahedral Al-Cu-Fe quasicrystal, consistent with the expectation that the electronic structure is of general importance in the stabilization of icosahedral phases. (iii) In icosahedral Al-Pd-Mn, the pseudogap of the bulk is not retained up to the surface immediately after fracture, but can be restored by annealing, or by sputter annealing to sufficiently high temperatures. Assuming that the pseudogap reflects an electronic stabilization of the atomic structure, these results suggest that the heat-treated surfaces are more stable thanmore » the surface obtained by fracturing at room temperature.« less