Ab initio description of laser-induced ultrafast phenomena in the presence of surfaces and interfaces

存在表面和界面时激光诱导超快现象的从头开始描述

基本信息

批准号：
328175242
负责人：
Professor Dr. Martin Ezequiel Garcia
金额：
--
依托单位：
Theoretische Physik II: Festkörper und Ultrakurzzeitphysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/328175242?language=en
关键词：
Ab initio description laser induced

项目摘要

Ultrafast phenomena induced by femtosecond-laser pulses are believed to be, in most cases, nonthermal or to have at least a nonthermal origin. There is plenty of experimental evidence for nonthermal structural phenomena. Effects like excitation of coherent phonons, phonon squeezing, ultrafast melting, bond-softening and hardening were either directly measured or inferred from measurements. Our group has a vast experience in successfully explaining and predicting nonthermal structural phenomena induced by ultrashort laser and XUV pulses. We developed the code CHIVES, able to perform ab initio molecular dynamics simulations of laser excited materials, and which has been shown to be about two hundred times faster than other ab initio codes with the same accuracy. Since many experiments, particularly those based on ultrafast electron crystallography, are performed on thin films and since most applications of laser-solid interactions are aimed at the processing (e.g., nanostructuring) of surfaces, it is a challenge for theory to simulate laser induced ultrafast phenomena on surfaces and in thin films. No ab initio theory of nonthermal effects on surfaces and in thin films could be performed so far. In this project we plan to simulate ultrafast non thermal phenomena (1) in silicon thin films, (2) in a Si/SiC superlattice, and (3) in a Si/SiC thin film. Due to technical reasons, for the atomistic description of these systems convergence is poor, which would make the simulations forbiddingly slow. Therefore, it is necessary to further speed up CHIVES by improving the convergence of the underlying self-consistent calculations. From the proposed simulations we expect to predict novel nonthermal effects, like, suppression of surface melting (preempting) or anomalous diffusion of C atoms at the Si/C interface, which might open a new field of research in nonequilibrium physics and lead to new applications.In addition, the treatment of a Si/SiC thin film is a first step towards a realistic description of oxidized surfaces.

飞秒激光脉冲诱导的超快现象被认为在大多数情况下是非热的或至少具有非热的起源。有很多非热结构现象的实验证据。通过测量直接测量或推断出相干声子激发，声子挤压，超快熔化，粘合熔化和硬化等影响。我们的小组在成功解释和预测超短激光和XUV脉冲引起的非热结构现象方面具有丰富的经验。我们开发了代码细胞，能够对激发材料进行初始分子动力学模拟，并且已显示其比其他准确性相同的其他AB启动代码快两百倍。由于许多实验，尤其是基于超快电子晶体学的实验，是在薄膜上进行的，并且由于激光 - 固定相互作用的大多数应用都针对表面的处理（例如，纳米结构），因此对于模拟激光诱导的超级临时，理论是一个挑战表面和薄膜中的现象。到目前为止，无法对表面和薄膜中的非热效应进行从头开始理论。在这个项目中，我们计划在硅薄膜中模拟超快非热现象（1），（2）在Si/SiC超晶格中，以及（3）在Si/SiC薄膜中。由于技术原因，对于这些系统收敛的原子描述很差，这将使模拟禁止缓慢。因此，有必要通过改善潜在的自洽计算的融合来进一步加快细胞的速度。从提出的模拟中，我们期望预测新的非热效应，例如，抑制表面熔化（先发制人）或在Si/c界面上C原子的异常扩散，这可能在非平衡物理学中开设一个新的研究领域，并导致新的应用。此外，对Si/SiC薄膜的处理是迈向氧化表面的现实描述的第一步。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Performance of state-of-the-art force fields for atomistic simulations of silicon at high electronic temperatures

高电子温度下硅原子模拟的最先进力场性能

DOI：
10.1140/epjst/e2019-800181-3
发表时间：
2019
期刊：
The European Physical Journal Special Topics
影响因子：
0
作者：
Bernd Bauerhenne;Martin E. Garcia
通讯作者：
Martin E. Garcia

Nonequilibrium dynamics of the phonon gas in ultrafast-excited antimony

DOI：
10.1103/physrevmaterials.1.073601
发表时间：
2017-12
期刊：
Physical Review Materials
影响因子：
3.4
作者：
S. Krylow;E. S. Zijlstra;Fairoja Cheenicode Kabeer;T. Zier;B. Bauerhenne;Martin E. Garcia
通讯作者：
S. Krylow;E. S. Zijlstra;Fairoja Cheenicode Kabeer;T. Zier;B. Bauerhenne;Martin E. Garcia

Simulations of laser-induced dynamics in free-standing thin silicon films