Diffusion of Au atoms and (5×2) phase formation on the Si(111) (7×7) surface

In this article we investigate the complex 1D mesoscopic model of adatom diffusion and the evolution of an ordered phase on the substrate surface. The analysis of the theoretical model is compared with the experimental results of the spreading of Au adatoms on Si(111)-(7×7) surface. The steady state solutions and their stability conditions are determined within the concept of the traveling-wave solution. It is shown that the formation of the ordered phase (5×2) and the difference in the diffusion of Au on (7×7) and on (5×2) structure results in a sharp edge of diffusion front which corresponds to the coverage of a saturated (5×2) phase. This edge moves linearly in time and α can be determined by experiment. The system of model equations enables the damped waves solution or temporary evolution of two steps.     

Si(111)-(7×7)表面上Ge量子点的自组织生长

用扫描隧道显微镜研究了Si(111)(7×7)表面上Ge量子点的自组织生长.室温下用固相外延法在硅基底上沉积亚单层的Ge,然后在适当的温度下退火可以聚集形成有序的Ge量子点.由于Ge在Si(111)(7×7)表面选择性的吸附而形成有序的Ge量子点. 关键词： 锗 硅 扫描隧道显微镜 自组织生长     

10~(-7)安积分电路

在核物理实验中,往往需要测知离子流的电量与离子流强度。比较简便的方法是用积分电路来测量电量,同时可指示离子流强度。本文所介绍的是一个实用的积分电路,其中包括直流放大,触发电路,计数电路及稳定电源等。离子流的强度由仪器上电流表指出,电量由机械记数器的数字来表示。     

Ag/Si(111)-(7X7) Heteroepitaxy—STM Experiment and KMC Simulations

Heteroepitaxial growth of Ag on Si(111)-(7X7) surface at various conditions was experimentally studied by scanning tunneling microscopy. A growth model based on experiments was used for kinetic Monte Carlo (KMC) simulations. The simulations of nucleation and island growth at low coverage and fitting experimental data provided basic growth parameters. Further growth—formation of a discontinuous transition film (wetting layer)—was implemented into the basic model. The suggested growth mechanism was successfully tested using the KMC simulations. The choice of experiments, the role of minimizing processes and parameters in the model, and efficiency of the used approach is demonstrated and discussed.     

Si(111)7×7结构模型的稳定性研究

本文基于有相互作用的结构件的概念,对Si(111)7×7结构模型的稳定性进行研究。利用紧束缚法,计算了各种结构件的形成能及其相互作用能。由这些结构件可灵活地构成各种大单胞的表面结构并对其进行总能计算,而避免了大工作量的计算。对Si(111)5×5和7×7DAS模型,我们得到其表面能分别为-0.467eV和-0.477eV,与Qian和Chadi的结果很接近。并指出,Harrison提出的7×7吸附原子模型和Binnig等人提出的7×7吸附原子-空位模型都是不稳定的。     

Adsorption of Perylene on Si(111)(7×7)

We investigate the adsorption of organic molecular semiconductor perylene on(7 × 7) reconstructed Si(111)surface by ultraviolet photoemission spectroscopy.It is observed that seven features that derive from the organic material are located at 0.71,2.24,4.0,5.9,7.46,8.65 and 9.95 eV in binding energy.The theoretical calculation results reveal the most stable adsorption geometry of organic molecule perylene on Si(111)(7 × 7) substrates is at the beginning of deposition.     

1993年(第7卷)主题索引

理论研究和数值模拟高加载率条件!:LY12铝合金损伤断裂现象的研究·············································…… .....................................·..·..·.……~·一“…王泽平黄风雷丁傲侠教铝、铜、铅压力熔化曲线的研究·············································……郑伟涛张瑞林Thomas一Fermi模峨的相对论修正·············································,····…     

Pd_(73) Si_(20)Cr_7合金的磁阻效应

本文报告了Pd_(73) Si_(20) Cr_7合金的磁阻测量结果.发现在4.2K之下,非晶态样品在低场区为正的磁阻效应,在高场区为负的磁阻效应.其峰值出现在几千到一万高斯的范围内.     

Ge在Si(111)7×7表面的选择性吸附

利用超高真空扫描隧道显微镜研究了室温条件下Ge在Si(111)7×7表面上初期吸附过程.在Ge所形成团簇中存在一个临界核.这些Ge团簇的吸附中心总是在三个增原子所围成的区域中.它们的电子结构具有类似半导体的性质,即其局域态密度在远离费米面的能级处很大,而在费米面附近的能级处非常小. 关键词： 扫描隧道显微镜 Si(111)7×7表面 Ge团簇     

Many-body effects in the Si(111)7×7 reconstructed surface

A two-dimensional Hubbard Hamiltonian is introduced in order to analyse the many-body effects associated with a dangling bond Si(111) 7×7 surface state located at the Fermi energy. Our results indicate that many-body effects can offer an explanation of recently reported experimental data.     

Si(111)7×7清洁表面的总电流谱

用自制的总电流谱仪对Si(111)7×7清洁表面进行了测量,得到A,B,C,D四个谱峰的能量位置分别在真空能级以上2.6,5.2,8.6和12.9eV。样品饱和吸氢后表面峰A消先。用带间跃迁模型对实验结果作了初步分析。 关键词：     

Highly site-selective adsorption of trimethylphosphine on a Si(111)-(7 × 7) surface studied by a scanning tunneling microscope (STM)

Adsorption of trimethylphosphine (TMP) on a Si(111)-(7 × 7) surface has been studied using a scanning tunneling microscope (STM). We find that most of the TMP molecules are adsorbed preferably on center adatom sites at the surface. It is observed that the TMP molecule on a corner adatom is moved to a center adatom site at RT. TMP is more stable on the center adatom sites than on the corner adatom sites.     

低温物理第7卷(1985)总目录

第1期二维Fer而液体理论··················································,·········……卢德馨蔡建华(1)JosePh沁”隧道结的临界厚度···················································……张裕恒刘宏宝(12)由多层无序合金膜组成的超晶格的声子结构,’···········································……熊诗杰(19)非晶态z‘一Si合金的超导临界温度·········…     

SU(7)模型的CP破坏问题

我们研究了包括四代的SU（7）大统一模型的CP破坏问题。结果表明,适当地选取夸克矩阵元及其复相位a_i（如文献[2]那样）,可以得到与实验相符的CP破坏,并且,适当地选取Hoggs势（如文献[2]那样）可以使强CP破坏参数θ在树图级为零而与实验相符。     

Si(111)7×7表面孤立C_(60)分子的吸附取向及局域电子态研究

利用低温扫描隧道显微镜对Si(111) 7× 7表面的孤立C60 分子成像 ,结合局域密度泛函方法计算 ,确定了C60 在不同吸附位置的分子取向 .同时进行的扫描隧道谱揭示了C60 吸附后的局域电子态 .     

1993年(第7卷)作者索引

二~五划(丁、于、支、王、车、毛、田、冯)T傲7(1)23于宝明7(4)286支全标7(1)33王私7(4)254王悟7(3)226王小兵7(l)75王丈强7(4)272王龙书7(3)177王立tf.7(3)183王永国7(l)54王汾菊7(3)202王全贵7(2)143王泽平7(1)23王未彦7(l)61王莉君7(3)202王积方7(2)123,7‘3)202王新济7(3)161王德荣7(2)105车荣枉t,(2)123,7(3)202毛友德7(2)156,7(4)301田德诚7(l)75冯庆田7(2)148冯禹辰7(3)167 六划(朱、刘、庄、池、汤、许、孙)朱艺兵7(4)293未道本7(3)202刘另7(l)l,7(3)220刘才学7(’l)54刘世超7(l)l刘冰冰7(3)183刘宏建7(3)167刘维娜7(l)37,7(3)167…     

STM light emission from Si(1 1 1)-(7 × 7) surface using a silver tip

Scanning tunneling microscope-light emission (STM-LE) from the Si(1 1 1)-(7×7) surface has been measured using silver tips. For silver tips photon emission was enhanced by more than 100 times as compared with that for tungsten or platinum–iridium alloy tips. A broad spectrum with a single peak at ∼2.25 eV was observed. The spectrum obtained can be reproduced by a theory based on the macroscopic dielectric response of the tip-sample system, indicating that the observed emission arises from the localized plasmons on the silver tip excited by tunneling electrons. Spatial variations in the emission intensity at the atomic scale was observed even under low bias voltage (2 V) and low tunneling current (1 nA) conditions.     

Si(111)-(7×7)衬底上合成有序的IV族金属铅团簇阵列

文章作者在Si(111)(7×7)衬底上合成出位于同一主族的Pb的全同纳米团簇有序阵列.有趣的是,当衬底温度相对于最佳的生长温度范围发生微小的偏离时,Pb纳米团簇很容易转变为其他结构的团簇.结合实验结果和第一性原理总能量计算,文章作者揭示了几种Pb团簇的原子结构.这些结构都是以表面Pb和Si原子互换导致的混合模型为中心的衍生结构.Pb/Si(111)体系的这种边缘性质为研究表面幻数团簇的合成、分解等动力学过程提供了重要信息.     

用低能电子衍射研究Si(111)7×7表面的原子结构

本文提出了一个由低能电子衍射能带理论计算所确定的Si(111)7×7表面的不等边三角形聚合与添加原子模型。发现:第一层空间距d_k=0.95±0.02?(膨胀21.3%±0.02?),第二层空间距d_l=0.83±0.02?(膨胀5.9%±0.02?),第三层空间距d_l=0.69±0.05?(收缩10.9%±0.08?)和第四层空间距d_b=2.38±0.08?(膨胀3.8%±0.08?)。