Stefano Falletta^1*, Alfredo Pasquarello^1*

1 Chaire de Simulation à l'Echelle Atomique (CSEA), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

* Corresponding authors emails: stefano.falletta@epfl.ch, alfredo.pasquarello@epfl.ch

DOI10.24435/materialscloud:fy-86 [version v1]

Publication date: Apr 28, 2023

How to cite this record

Stefano Falletta, Alfredo Pasquarello, Polaron hopping through piecewise-linear functionals, Materials Cloud Archive 2023.70 (2023), doi: 10.24435/materialscloud:fy-86.

Description

We use piecewise-linear functionals to study the polaron energy landscape and hopping rates in 𝜷-Ga₂O₃, which we adopt as an example of an anisotropic material hosting multiple polaronic states. We illustrate various functionals for polaron localization, including a hybrid functional and two types of semilocal functionals, and discuss how to ensure the piecewise linearity condition. Then, we determine the formation energies of stable polarons, and show that single-site and multi-site polaronic states can be found in close energetic competition. We calculate the hyperfine and superhyperfine parameters associated with each polaron, and discuss the comparison with experiment. Next, we perform nudged-elastic-band calculations to determine energy landscapes and hole transfer rates of all first-nearest-neighbor polaron hoppings. We show that when the piecewise linearity condition is ensured polaron properties are robust upon variation of the functional adopted, including formation energies, energy barriers, and charge transfer rates. This supports the use of semilocal functionals for calculating polaron transport properties.

Materials Cloud sections using this data

Files

File name	Size	Description
structures.zip MD5md5:9eff93eef0dba3692add34ff11b1f573	122.6 KiB	Bulk and polaron structures obtained with the various piecewise-linear functionals
NEB.zip MD5md5:10fc97e8f22123e160f4f3bc231a61a5	890.7 KiB	NEB trajectories and energy profiles, as obtained with gammaDFT and DFT+U
README.xyz MD5md5:e7fb2d4c5e85bfd4bb403e0ff9d57ff4	7.1 KiB	README

License

Files and data are licensed under the terms of the following license: Creative Commons Attribution 4.0 International.
Metadata, except for email addresses, are licensed under the Creative Commons Attribution Share-Alike 4.0 International license.

External references

Keywords

density-functional theory polarons piecewise linearity DFT+U hybrid functionals gammaDFT self-interaction polaron hopping