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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.

飞秒激光脉冲引起的超快现象被认为是，在大多数情况下，非热或至少有一个非热的起源。非热结构现象有大量的实验证据。相干声子的激发、声子压缩、超快熔化、键软化和硬化等效应可以直接测量或从测量中推断出来。我们的团队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拥有丰富的经验。我们开发的代码CHIVES，能够进行从头算分子动力学模拟的激光激发的材料，并已被证明是约200倍的速度比其他从头算代码具有相同的精度。由于许多实验，特别是那些基于超快电子晶体学的实验，都是在薄膜上进行的，并且由于激光-固体相互作用的大多数应用都是针对处理（例如，纳米结构）的表面，这是一个挑战的理论模拟激光诱导超快现象的表面和薄膜。没有从头算理论的非热效应的表面和薄膜可以执行至今。在这个项目中，我们计划模拟超快非热现象（1）在硅薄膜，（2）在Si/SiC超晶格，（3）在Si/SiC薄膜。由于技术原因，对于这些系统的原子描述收敛性差，这将使得模拟速度非常慢。因此，有必要通过提高底层自洽计算的收敛性来进一步加速CHIVES。从所提出的模拟，我们希望预测新的非热效应，如抑制表面熔化（抢占）或异常扩散的C原子在Si/C界面，这可能会打开一个新的领域的非平衡物理研究，并导致新的应用。此外，处理的Si/SiC薄膜是第一步走向现实的描述氧化表面。

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

Controlling Three Laser-Excited Coherent Phonon Modes in Boron Nitride Nanotubes To Produce Ultrashort Shaped Terahertz Pulses: Implications for Memory Devices