共查询到18条相似文献,搜索用时 187 毫秒
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为了探讨非完整基底结构对生长表面动力学行为的影响,本文在具有相同分形维数而不同谱维数的谢尔宾斯基箭头和蟹状分形基底上对受限固-固(restricted solid-on-solid,RSOS)模型的生长过程进行了大量的数值模拟研究.通过计算表面宽度和饱和表面极值高度的统计行为对生长表面的动力学行为进行了分析.结果表明,分形基底结构对生长表面的动力学行为具有显著的影响.尽管在两种基底上受限固-固模型的表面宽度均表现出很好的动力学标度行为,仍然满足Family-Vicsek标度规律,但由此计算得到的动力学标度指数并不相同.饱和生长表面的极值高度并不能满足三种常用的极值统计分布,即Weibull,Gumbel和Frechet分布,而是能很好地符合Asym2Sig分布. 相似文献
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为分析基底结构对离散生长模型动力学性质的影响, 本文在随机游走指数十分接近而分形维数和谱维数均不相同的科赫格子和科赫曲线分形基底上对受限固-固(restricted solid-on-solid)模型的生长过程进行数值模拟研究. 通过分析表面宽度和饱和表面极值高度的统计行为发现: 随机游走的动力学指数能够对饱和粗化表面的动力学行为起主要贡献. 尽管分形基底具有不同的分形维数和谱维数, 但是在两种分形基底上得到了在误差范围内相同的粗造度指数. 两种分形基底上饱和表面相对生长高度极大(小)值分布分别可以很好的塌缩在一起, 且很好的满足Asym2Sig函数分布. 相似文献
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为全面研究Wolf-Villain(WV)模型生长表面的统计性质,基于极值统计理论,模拟计算1+1维WV模型在饱和生长阶段表面的极大高度分布(maximal-height distribution,MAHD)和极小高度分布(minimal-height distribution,MIHD).结果表明,MAHD和MIHD在不同的系统尺寸下分别有较好的标度规律,这两个分布之间存在不对称性.其中,MAHD遵循-种常见的极值分布,即广义的Fisher-Tippett-Gumbel(FTG)型分布;而MIHD可以用-个修正的Fisher-Tippett-Gumbel(MFTG)型分布来描述. 相似文献
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为研究表面界面粗化生长中孔洞的标度行为,在对Ballistic Deposition(BD)模型进行数值模拟的基础上,对模型中孔洞的模拟生长情况进行统计和分析.结果表明,BD模型中孔洞数目随模型生长时间的变化从初始阶段的高于线性而渐趋近于线性,并对该规律进行理论分析. 相似文献
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表面界面动力学粗化过程是凝聚态物理领域重要的研究内容,为研究基底不完整性对刻蚀模型动力学 标度行为的影响,本文采用Kinetic Monte Carlo(KMC)方法,分析研究了在随机稀释基底上刻蚀模型(Etching model)生长表面的动力学标度行为.研究发现:尽管随机稀释基底的不完整性会对刻蚀表面的动力学 行为产生显著的影响,导致刻蚀表面粗糙度指数和生长指数有明显的增加, 但其仍基本满足原有的动力学标度规律.此外,本文还对刻蚀表面动力学标度指数的有限尺寸效应进行了 分析讨论. 相似文献
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为了更全面、有效地研究刻蚀模型(etching model)涨落表面的统计性质,基于Schramm Loewner Evolution(SLEκ)理论,对2+1维刻蚀模型饱和表面的等高线进行了数值模拟分析.研究表明,2+1维刻蚀模型饱和表面的等高线是共形不变曲线,可用Schramm Loewner Evolution理论进行描述,且扩散系数κ=2.70±0.04,属κ=8/3普适类.相应的等高线分形维数为df=1.34±0.01. 相似文献
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石墨烯等材料具有典型的二维蜂巢结构,而随机电阻丝模型则是研究非均匀材料断裂十分有效的统计物理学模型.本文尝试对二维蜂巢结构随机电阻丝网络熔断的动力学过程及熔断面性质进行数值模拟分析,以此来研究二维非均质蜂窝材料熔断的动力学性质和熔断面的动力学标度性质.模拟研究表明,二维随机蜂窝网格的熔断动力学过程和熔断面具有明显的标度性质,得到的熔断面整体和局域粗糙度指数分别为α=0.911±0.005和α_(loc)=0.808 ± 0.003,这两者之间的明显差异表明熔断面具有奇异标度性.通过对熔断面极值高度的分析发现,熔断面高度的极值统计分布能很好地满足Asym2sig型分布,而不是最常见的三种极值统计分布.本文的研究表明,随机电阻丝模型在模拟非均匀材料的电流熔断过程和熔断表面标度性的分析中同样适用和有效. 相似文献
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应用晶体相场方法模拟研究金属微互连结构形变过程对界面Kirkendall空洞生长的抑制作用。主要研究在金属微互连结构对称界面不同取向差的情况下,双向恒定速率应变对Kirkendall空洞微观组织及生长动力学的影响。研究结果表明:金属微互连结构界面在双向恒定速率应变作用下有非晶化趋势,界面原子错配度和缺陷密度增大,进而抑制Kirkendall空洞的生长;双向恒定速率应变不改变Kirkendall空洞在对称界面取向差情况下的形核方式,Kirkendall空洞的形核方式为体系形核点饱和后的晶界形核;Kirkendall空洞在金属微互连结构小角度对称和大角度对称界面皆为均匀分布;随着演化时间的延长Kirkendall空洞平均尺寸和面积均逐渐增大;随着小角度对称界面取向差的增大Kirkendall空洞平均尺寸、面积和生长指数均逐渐降低;随着大角度对称界面取向差的增加,Kirkendall空洞平均尺寸和面积逐渐减小,而生长指数逐渐增大。双向恒定速率应变可有效减小Kirkendall空洞生长尺寸和面积,抑制Kirkendall空洞的生长,进而提升金属微互连结构的可靠性。 相似文献
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Mathew D. Penrose 《Journal of statistical physics》2008,131(2):247-268
In ballistic deposition (BD), (d+1)-dimensional particles fall sequentially at random towards an initially flat, large but bounded d-dimensional surface, and each particle sticks to the first point of contact. For both lattice and continuum BD, a law of
large numbers in the thermodynamic limit establishes convergence of the mean height and surface width (sample standard deviation
of the height) of the interface to constants h(t) and w(t), respectively, depending on time t. We show that h(t) is asymptotically linear in t, while (w(t))2 grows at least logarithmically in t when d=1. We use duality results showing that w(t) can be interpreted as the standard deviation of the height for deposition onto a surface growing from a single point. 相似文献
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R.G. da Silva M.L. Lyra C.R. da Silva G.M. Viswanathan 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,17(4):693-697
In this work, we introduce a restricted ballistic deposition model with symmetric growth rules that favors the formation of
local finite slopes. It is the simplest model which, even without including a diffusive relaxation mode of the interface,
leads to a macroscopic groove instability. By employing a finite-size scaling of numerical simulation data, we determine the
scaling behavior of the surface structure grown over a one-dimensional substrate of linear size L. We found that the surface profile develops a macroscopic groove with the asymptotic surface width scaling as , with . The early-time dynamics is governed by the scaling law , with . We further investigate the sensitivity to initial conditions of the present model by applying damage spreading techniques.
We find that the early-time distance between two initially close surface configurations grows in a ballistic fashion as , but a slower Brownian-like scaling () sets up for evolution times much larger than a characteristic time scale .
Received 26 May 2000 相似文献
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Mound morphology of the 2+1 -dimensional Wolf-Villain model caused by the step-edge diffusion effect
The mound morphology of the 2+1-dimensional Wolf-Villain model is studied by numerical simulation. The diffusion rule of this model has an intrinsic mechanism, i.e., the step-edge diffusion, to create a local uphill particle current, which leads to the formation of the mound. In the simulation, a noise reduction technique is employed to enhance the local uphill particle current. Our results for the dynamic exponent 1/z and the roughness exponent α obtained from the surface width show a dependence on the strength of the step-edge diffusion. On the other hand, λ(t), which describes the separation of the mounds, grows as a function of time in a power-law form in the regime where the coalescence of mounds occurs, λ(t)∼tn, with n≈0.23-0.25 for a wide range of the deposition conditions under the step-edge diffusion effect. For m=1, a noise reduction factor of unity, the behavior of λ(t) in the saturated regime is also simulated. We find that the evolution behavior of λ(t) in the whole process can be described by the standard Family-Vicsek scaling. 相似文献
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R. P. Chiarello H. You H. K. Kim T. Roberts R. T. Kempwirth D. Miller K. E. Gray K. G. Vandervoort N. Trivedi S. R. Phillpot Q. J. Zhang S. Williams J. B. Ketterson 《Surface science》1997,380(2-3):245-257
We performed in-situ X-ray reflectivity measurements of gold films during sputter deposition on polished silicon substrates. The measurements were performed at several substrate temperatures and under two argon pressures. The gold surfaces were also examined by scanning tunneling microscopy after deposition to obtain their real-space topographic images. These images were used to complement the X-ray reflectivity measurements in determining the effect of argon pressure on the gold surface and its height-height difference functions. An approximation for height-height difference functions was employed to analyze the X-ray reflectivity data. The measured interface width during growth followed a simple power law, consistent with recent theoretical results of dynamic scaling behavior. The scaling exponents, however, do not agree well with predictions based on some models in 2 + 1 dimensions. 相似文献
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沉积工艺对二氧化锆薄膜生长特性影响的研究 总被引:3,自引:2,他引:1
利用反应离子束溅射、反应磁控溅射和电子束蒸发在K9基底上沉积ZrO2薄膜,并用原子力显微镜对薄膜表面形貌进行测量。通过数值相关运算,对不同工艺条件下薄膜生长界面进行定量描述,得到了薄膜表面的粗糙度指数、横向相关长度、标准偏差粗糙度等参量。由于沉积条件的不同,薄膜生长具有不同的动力学过程。在反应离子束溅射和反应磁控溅射沉积薄膜过程中,薄膜生长动力学行为均可用Kuramoto-Sivashinsky方程来描述,电子束蒸发制备薄膜的过程可以用Mullins扩散模型来描述,并发现在沉积薄膜过程中基底温度和沉积过程的稳定性对薄膜表面特征影响很大。 相似文献