Electronic and thermal properties of the phase-change memory material, Ge2Sb2Te5, and results from spatially resolved transport calculations
: Nepal, K.; Gautam, A.; Hussein, R.; Konstantinou, K.; Elliott, S.R.; Ugwumadu, C.; Drabold, D.A.
Publisher: Elsevier BV
: 2026
Solid State Sciences
: 108182
: 173
: 1293-2558
: 1873-3085
DOI: https://doi.org/10.1016/j.solidstatesciences.2025.108182
: https://doi.org/10.1016/j.solidstatesciences.2025.108182
We report new insights into the electronic, structural, and transport (heat and charge) properties of the phase-change memory material amorphous Ge2Sb2Te5. Using realistic structural models of Konstantinou et al., (2019), we analyze the topology, electronic states, and lattice dynamics with density functional methods, including hybrid-functional calculations and machine-learned interatomic potentials. The Kohn–Sham orbitals near the Fermi level display a strong electron–phonon coupling, and exhibit large energy fluctuations at room temperature. The conduction tail states exhibit larger phonon-induced fluctuations than the valence tail states. To resolve transport at the atomic scale, we employ space-projected electronic conductivity and site-projected thermal conductivity methods. Local analysis of heat transport highlights the role of filamentary networks dominated by Te, with Sb and Ge making progressively smaller contributions.
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The computational resource used in this work was supported by the US National Science Foundation (NSF) under award number MRI2320493 and the Office of Naval Research, United States under grant N000142312773. K. N. acknowledges financial support from the Nanoscale & Quantum Phenomena Institute (NQPI), United States, conferred through the NQPI graduate research fellowship. K.K. acknowledges financial support from the Research Council of Finland under grant no. 364241 (“NoneqRSMSD”). S.R.E. is grateful to the Leverhulme Trust (UK) for a Fellowship. C. U. acknowledges funding from the Laboratory Directed Research and Development program of Los Alamos National Laboratory, United States under the Director’s Postdoctoral Fellowship Program, project number 20240877PRD4. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration, United States [http://dx.doi.org/10.13039/100006168] of the U.S. Department of Energy (Contract No. 89233218CNA000001).
