Structural and electronic properties of thallium overlayers on the Si(111)-7x7 surface
Structural and electronic properties of thallium overlayers on the Si(111)-7x7 surface
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DOI：
10.1103/physrevb.66.233312
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发表时间：
2002-12-15
影响因子：
3.7
通讯作者：
Tochihara, H
中科院分区：
文献类型：
--
作者：
Lee, SS;Song, HJ;Tochihara, H
我们研究了在Si（111）-7x7表面上形成的有序的铊覆盖层结构的原子排列及其电子性质。至于其他三价原子，发现T1形成明确定义的root 3xroot 3表面，表明不存在仅针对T1考虑的所谓“惰性对效应”。另一个有序的1x 1表面在1.0单层似乎是半导体在我们的角度分辨的光电子能谱由一个独特的色散表面带附近的费米能级为主。我们的理论计算使用密度泛函理论表明，Tl吸附原子占据的T-4网站和饱和的表面Si原子的所有悬挂键，使表面半导体与0.34 eV的带隙。在我们的能带计算中，观察到的填充表面能带得到了很好的再现。
We have investigated atomic arrangements and their electronic properties of the well-ordered thallium overlayer structures formed on the Si(111)-7x7 surface. As for other trivalent atoms, Tl is found to form a well-defined root3xroot3 surface, indicating the absence of a so-called "inert pair effect" considered only for Tl. Another well ordered 1x1 surface at 1.0 monolayer appears to be semiconducting in our angle-resolved photoemission spectra dominated by a unique dispersive surface band near the Fermi level. Our theoretical calculations using density-functional theory show that Tl adatoms occupy the T-4 sites and saturate all the dangling bonds of surface Si atoms to make the surface semiconducting with a band gap of 0.34 eV. The filled surface band observed has been well reproduced in our band calculations.