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Title: Stability and migration of small copper clusters in amorphous dielectrics

We use density functional theory (DFT) to study the thermodynamic stability and migration of copper ions and small clusters embedded in amorphous silicon dioxide. We perform the calculations over an ensemble of statistically independent structures to quantify the role of the intrinsic atomic-level variability in the amorphous matrix affect the properties. The predicted formation energy of a Cu ion in the silica matrix is 2.7 ± 2.4 eV, significantly lower the value for crystalline SiO{sub 2}. Interestingly, we find that Cu clusters of any size are energetically favorable as compared to isolated ions; showing that the formation of metallic clusters does not require overcoming a nucleation barrier as is often assumed. We also find a broad distribution of activation energies for Cu migration, from 0.4 to 1.1 eV. This study provides insights into the stability of nanoscale metallic clusters in silica of interest in electrochemical metallization cell memories and optoelectronics.
Authors:
; ;  [1]
  1. School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907-2044 (United States)
Publication Date:
OSTI Identifier:
22410235
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ACTIVATION ENERGY; COMPARATIVE EVALUATIONS; COPPER; COPPER IONS; DENSITY FUNCTIONAL METHOD; DIELECTRIC MATERIALS; ELECTROCHEMISTRY; EV RANGE; FORMATION HEAT; MATRIX MATERIALS; NANOSTRUCTURES; NUCLEATION; SILICA; SILICON OXIDES