Multi-modal Energy Flow at Atomically Engineered Interfaces
Abstract
Maria Group: The Maria Group and MURI collaborators endeavor to understand how multilayered thin film systems that are promoted to high and non-thermal equilibrium states decay back to kT. Specifically, we wish to understand the mechanisms by which these energy transduction events occur, under the speculation that different ones predominate over shorter (i.e., ps-to-ns) and longer (i.e., µs-to-ms) time scales. Ultimately, we wish to understand how the structure, chemistry, and geometry of a specific interface regulates both the short-term and long-term mechanisms, and how the two may be linked. The heterostructures that we explore fall into two categories: 1) metal|metal oxide multilayers; and 2) by high mobility conducting metal oxide semiconductors and junctions that are promoted to high energy states by intense deep-subwavelength plasmonic absorption. Dlott Group: This MURI sub is an experimental study of mutimodal interfacial processes, chemical reactions that are strongly coupled to mechanical dynamics at fuel/oxidizer interfaces. The goal is to characterize fast energetic interfacial chemical processes under extreme conditions of shock compression or flash-heating. The objectives are to develop a fundamental understanding at the atomic scale of high-energy nonequilibrium interfacial processes. Parsons Group: The key objective in ParsonsÕ group research in the MURI is to understand how organic/inorganic interface chemical bonding and structure influences energy transfer under highly non-equilibrium conditions over milli- to pico-second time scales. Using chemical surface and interface control enabled by novel atomic and molecular layer deposition and etching tools developed in our laboratory, we provide MURI team members with platform materials to observe energy transfer via nanoscale mechanical shock (i.e. flyer plate), plasmonic absorption, and time domain thermal reflectance. Brenner Group: Our objective is to use modeling approaches and boundary conditions that are appropriate for the time and length scales appropriate for reactive nanolaminates (RNLs) that are subject to intense mechanical shock. Molecular dynamics (MD) simulations will be used to directly model chemical and physical processes during shock loading. From these simulations the degree of diffusion, chemical energy release, and the formation of defects (e.g. dislocations, interface de-bonding) during shock compression and unloading will be characterized, with the goal of unraveling the detailed processes leading to reaction initiation. Prezhdo Group: The tools of real-time time-dependent density functional theory (TDDFT) and non-adiabatic molecular dynamics (NAMD) developed in Prezhdo group are used to perform quantum mechanical modeling of energy transduction involving multiple electronic and vibrational degrees of freedom at atomically engineered interfaces excited to high energy states, in close collaboration with experiment. The state-of-the-art non-equilibrium TDDFT and NAMD approaches are employed to elucidate the detailed atomistic mechanisms and timescales of... Hopkins Group:...
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 04, 2018
- Source ID
- W911NF1610406
Entities
People
- Donald W. Brenner
Organizations
- Army Contracting Command
- North Carolina State University
- United States Army