The Influence of Structure on the Itinerant Band Structure of Thin Metal Overlayers

通过改变薄膜的晶体结构和晶格参数可以改变薄膜的电子能带结构。结合角分辨光电发射和低能电子衍射(LEED)等强大的表面科学技术，将研究晶体和能带结构之间的关联。通过在精心选择的晶体衬底上外延生长覆盖层，将迫使覆盖层形成不寻常的晶体几何形状和晶格间距。调查将集中于从IIa和IIb元素和惰性气体中选择的选定覆盖层材料。利用光电子能谱确定价带结合能与布里渊区位置的函数关系，可以研究覆盖层的能带结构。这种传统的确定能带结构的方法将被一种新的方法所补充，该方法包括分析价轨道的相对光离部分截面作为光子能量的函数。LEED将被用来通过比较LEED强度与电子加速电压的动态LEED计算来研究覆盖层晶格结构。通过将光电子能谱和原子束散射两种技术结合起来研究薄(0-10)单层膜，可以深入了解原子轨道重叠的重要性和许多电子效应对电子能带结构的影响。

The electronic band structure of thin film overlayers can be altered by changing the crystal structure and lattice parameters. The correlation between crystal and band structures will be investigated by combining the powerful surface science techniques of angle-resolved photoemission and low energy electron diffraction (LEED). Overlayers will be forced into unusual crystal geometries and lattice spacings by epitaxially growing the overlayer on carefully chosen crystal substrates. The investigation will concentrate on selected overlayer materials chosen from the IIa and IIb elements and the noble gases. The band structure of the overlayers can be investigated by using photoemission to determine the binding energies of the valence bands as a function of the position in the Brillouin zone. This traditional technique of determining band structure will be complemented by a new method that consists in analyzing the relative photo-ionization partial cross-section of valence orbitals as a function of photon energy. LEED will be used to investigate the overlayer crystal lattice structure by comparing LEED intensity versus electron accelerating voltages with dynamical LEED calculations. By combining the two techniques of photoemission and atom beam scattering in the investigation of thin (0-10) monolayer films, insight into the importance of atomic orbital overlap and many electron effects upon electronic band structure will be provided.