OPERANDO STUDIES OF ATOMICALLY PRECISE MATERIALS
Abstract
This proposal is centered on understanding how the interplay of structure, bonding, chemical order-disorder, thermodynamics and kinetics in atomically engineered materials drives them into different phases under the influence of external stimuli. Using chalcogenide-based phase change materials (PCMs) as a model system, single-crystalline Ge-Sb-Te alloys will be synthesized with control over composition, morphology, size, growth direction and cation (Ge-Sb) ordering or disordering in different planes. The open and lateral geometry of precisely synthesized nanowire systems will be studied by in situ probing techniques to obtain atomic-level insights into the structural and electronic evolution of the system driven by external fields via systematic addition of disorder. In these systems, interplay of bonding hierarchy, bond distortions, entropic mixing of atoms driven by chemical and electrical forces and coherent motion of extended defects lead to structural transitions or materials failure, which will be studied using synthesized materials in different starting states to obtain a comprehensive understanding of their response to external stimuli. As states evolve, their electronic properties will be characterized, and their stability measured to map out the complex energy landscapes along the reaction pathway. This proposal also aims at uncovering a much lower energy, non-melt quench, defect-based phase transformation. These studies will help guide the design of superior materials useful for energy efficient nonvolatile memory and neuromorphic devices that are also more immune to failure. Our proposed studies will lead to a better understanding of how disorder and its evolution influences materials properties and in general for understanding a variety of phenomena in complex chalcogenides, which are also useful for thermoelectric and other applications, all relevant to the DoD’s vision for developing novel devices and systems with unprecedented response.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 29, 2024
- Source ID
- FA95502310189
Entities
People
- Ritesh Agarwal
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Pennsylvania