Interplay Between Electronic and Ionic Processes at Grain Boundaries of Polycrystalline Oxides
EMSL Project ID
39949
Abstract
The main objective of this project is to investigate the interplay between electronic and ionic processes at grain boundaries of polycrystalline oxides, such as MgO, stabilized cubic ZrO2 and monoclinic HfO2, using state-of-the-art first principles computational techniques. We will address several important and challenging questions concerning the electronic properties of nanocrystalline metal-oxide materials: 1) What is the interplay between electron trapping and defect mobility at interfaces in the formation of the space charge layer? 2) How electronic and chemical properties of interfaces differ from those in the bulk material? 3) What are the mechanisms of incorporation of O2 and H2O? 4) What are the barriers for O ion diffusion along and across the GBs? We will use ab initio thermodynamics to relate the elementary, atomic scale total energies (calculated using periodic and embedded cluster methods) of these three or four component systems to thermodynamic potentials. To carry out the proposed research we will combine the periodic and embedded cluster calculations. The new methodology we propose to develop will be mainly concerned with applying an embedded cluster method implemented in the NWChem-Guess code to multi-component ionic-covalent compounds such as ZrO2:(Y,Sc). Exploring the state-of-the-art NWChem-Guess embedded cluster approach, which has been implemented within the framework of the NWChem quantum chemistry package, is one of the main objectives of this project. We plan to use this capability, develop it further as needed and then apply it to study the interplay between ion diffusion and dynamics of electron and hole polarons at interfaces.The project is driven by applications of these materials as catalytic substrates and electrolytes in solid oxide fuel cells (SOFC) and as dielectric insulating films in microelectronics. The results will be also relevant to applications of nanocrystalline metal-oxides materials in varistors, resistive memory devices and magnetic tunnel junctions, where ionic diffusion at GBs plays the major role. The calculations will be carried out in strong collaboration with extensive Fuel Cell, Materials and Catalysis programs at PNNL. To fulfill this challenging and computationally demanding project we request 250K hours of computer time spread over the duration of the project (3 years).
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-01
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Mckenna KP. 2013. "Electronic and Chemical Properties of a Surface Terminated Screw Dislocation in MgO." Journal of the American Chemical Society 135(50):18859-18865. doi:10.1021/ja408342z
Mckenna KP, AL Shluger, V Iglesias, M Porti, M Lanza, and G Bersuker. 2011. "Grain boundary mediated leakage current in polycrystalline HfO2 films ." Microelectronic Engineering 88(7):1272-1275. doi:doi:10.1016/j.mee.2011.03.024
Mckenna KP, and AL Shluger. 2011. "Electron and Hole Trapping in Polycrystalline Metal Oxide Materials." Royal Society of London. Proceedings A. Mathematical, Physical and Engineering Sciences 467(2131):2043-2053. doi:10.1098/rspa.2010.0518
Mckenna KP, and AL Shluger. 2013. "Structure and Electronic Properties of Polycrystalline Dielectrics." ECS Transactions 54(1):243-253. doi:10.1149/05401.0243ecst
Mckenna KP, D Koller, A Sternig, N Siedl, N Govind, PV Sushko, and OE Diwald. 2011. "Optical Properties of Nanocrystal Interfaces in Compressed MgO Nanopowders." ACS Nano 5(4):3003–3009. doi:10.1021/nn200062d
Shluger AL, KP Mckenna, PV Sushko, DM Ramo, and AV Kimmel. 2009. "Modelling of electron and hole trapping in oxides." Modelling and Simulation in Materials Science and Engineering 17(084004):21. doi:10.1088/0965-0393/17/8/084004