ElectronicStructureModels.jl

Overview

ElectronicStructureModels.jl is an open-source Julia package providing models from electronic-structure theory for use in larger simulations and data analysis workflows. It is designed with a focus on applications in X-ray Thomson Scattering (XRTS), but the components are general enough to be used in a broader context involving electron-gas models and response functions.

Key Features

The package currently includes:

Dynamic structure factors (DSF) for the uniform electron gas; including the finite-temperature Lindhard function within the Random Phase Approximation (RPA)
Several approximation levels for evaluating DSF and related quantities
A clean, extensible interface for adding new electronic-structure models in the future

Installation

The package is not registered yet. To install it locally:

git clone https://github.com/JuliaXRTS/ElectronicStructureModels.jl.git
cd ElectronicStructureModels.jl
julia --project -e "import Pkg; Pkg.build()"

Then in Julia:

using Pkg
Pkg.activate(".")
Pkg.instantiate()

This will also install required dependencies such as Unitful.jl.

Quickstart Example

Below is a minimal example showing how to construct an electron system and compute a dynamic structure factor. The example uses CairoMakie for plotting, but any plotting backend can be used.

using ElectronicStructureModels
using Unitful
using CairoMakie

NE   = 10e23u"cm^(-3)"   # electron density
TEMP = 1.0u"eV"          # temperature

ideal = IdealElectronSystem(NE, TEMP) # idear proper system
esys  = InteractingElectronSystem(ideal, Screening()) # RPA screening model

KF = fermi_wave_vector(esys) # Fermi wave vector (for scaling)
EF = fermi_energy(esys) # Fermi energy (for scaling)

ω_arr = range(1e-4, 6, 100) .* EF # array of energy transfer values
q     = 1.6 * KF # momentum transfer value

# calculation of the DSF
dsf_values = [dynamic_structure_factor(esys, (ω, q)) for ω in ω_arr]


# Plotting of the DSF as a function of the energy transfer normalized to unit height.
fig = Figure()
ax  = Axis(fig[1,1])

norm = maximum(dsf_values)
lines!(ax, ω_arr ./ EF, dsf_values ./ norm)

display(fig)

Contributing

Contributions of all kinds are welcome. Please read the contributing guide or its rendered version in the online documentation before opening pull requests or issues.

Credits and Funding

This work has been partially supported by the Center for Advanced Systems Understanding (CASUS), funded by the German Federal Ministry of Education and Research (BMBF) and the Saxon Ministry for Science, Culture and Tourism (SMWK) with tax funds based on the budget approved by the Saxon State Parliament.

Acknowledgements

Special thanks to Tobias Dornheim for funding, valuable input and support.