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Lattice dynamics of disordered phases of silicon and spatially resolved computations of thermal conductivity
A. Gautam, C. Ugwumadu, L. A. M. Rosset +3
The lattice dynamics of disordered systems (amorphous solids, polymers and glasses) are often distinct from crystalline analogues. Examples include the "two-level systems" and the…
Intrinsic Defects in Amorphous Optical Coatings of TiO-doped GeO for Gravitational-wave Detectors
K. Prasai, K. Lee, R. Bassiri +6
The increased laser power of future gravitational-wave detectors will require mirror coatings with optical absorption below 0.1 ppm per mirror. TiO-doped GeO, currently the…
Real-Space Mapping of Electronic Conductivity in Complex Materials
C. Ugwumadu, D. A. Drabold, R. M. Tutchton
We introduce KuboMap, a real-space representation of electronic conductivity derived from the Kubo-Greenwood formula. KuboMap defines a nonnegative conductivity density whose spati…
A Defect-Free Model of Amorphous Silicon with Pristine Electronic Structure
Louise A. M. Rosset, Chinonso Ugwumadu, Stephen R. Elliott +2
Amorphous silicon (a-Si) is understood to be the canonical continuous random network material, ideally defined by fully fourfold coordination. Here, we show that a defect-free ('id…
Seamlessly joining length scales: From atomistic thermal graphs to anisotropic continuum conductivity
C. Ugwumadu, D. A. Drabold, R. M. Tutchton
Thermal transport in complex solids is governed by local structure, defects, and anisotropy, yet most continuum models still rely on oversimplified, homogenized conductivities. Her…
Temperature dependence of electronic conductivity from ab initio thermal simulation
Ridwan Hussein, Chinonso Ugwumadu, Kishor Nepal +3
We present a temperature-dependent extension of the approximate electronic conductivity formula of Hindley and Mott that leverages time-averaged fluctuations of the electronic dens…