Computational Materials Physics

quick start
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practical info
about you
setting the stage
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the creation of materials from thought
the ab initio way  
solids as quantum systems
so what’s the problem?
advantages
theory versus computation
hardware
software
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webinar (w1)
density functional theory 
24 Topics
a DFT teaser
functions and functionals
the Schrödinger equation
the Born-Oppenheimer approximation
(post-)Hartree-Fock method(s)
the external potential
the electron density
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for project only (w2)
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first Hohenberg-Kohn theorem
second Hohenberg-Kohn theorem
Kohn-Sham equations
XC-functional
correlation
Hartree-Fock versus DFT
numerical solution methods
for later use
(optional) basis sets in more depth
(optional) back to the teaser
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crystallography
8 Topics
CIF files and how to find them
what’s in a cif ?
more useful tools
(optional) more on crystallography
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geometry optimization
18 Topics
hands-on task
step 1: volume optimization
bulk modulus and pressure
step 2: cell shape
upload your answer (geom 1)
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introduction to forces
classical forces
quantum forces
symmetry and forces
step 3: position optimization
full optimization
phase diagrams
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electronic structure
8 Topics
reciprocal space
plane waves and the reciprocal lattice
quantum numbers
plotting wave functions and densities
quantum numbers for a crystal
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chemical bonding
8 Topics
chemical bonding in textbooks
cohesive energy problem
chemical bonding from DFT
an old puzzle
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only for project (w8)
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elasticity
9 Topics
elastic constants: definition
computing elastic constants
applications of elastic constants
a hard example ;-)
a database of elastic constants
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supercells and surfaces
3 Topics
concept and uses
surface properties
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precision and accuracy
6 Topics
P&A lecture
P&A tasks
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for project only (w10)
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magnetism
4 Topics
spin magnetism
orbital magnetism
long-range magnetic order
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phonons and temperature
4 Topics
the basics of phonons
the Phonopy code : a guided example
phonons by QE + visualizer
soft modes and phase transitions
band gaps
2 Topics
which gap?
gap predictions
let’s play!
17 Topics
setting the stage – prepare your environment
setting the stage – HPC info (Flanders only)
setting the stage – help section
density functional theory 1 – a basic calculation
density functional theory 2 – basis set size and k-mesh
density functional theory 2 – convergence testing
crystallography – crystal viewers
crystallography – from cif to DFT input
geometry optimization – geometry: towards the ground state
geometry optimization – geometry: E(V) and EOS
electronic structure – band structure and DOS
chemical bonding – charge density difference plots
elasticity – elasticity
supercells and surfaces – creating supercells
supercells and surfaces – work function
magnetism
a frozen phonon calculation
project
8 Topics
w2 – project 2024-2025
w2 – assessment choice / sign up for project
w4 – project milestone 1
w8 – project milestone 2
w9 – online writing in latex
w12 – submit your project
w12 – gallery of project results (2024)
w12 – self-assessment and team introspection
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phonons by QE + visualizer

Computational Materials Physics phonons and temperature phonons by QE + visualizer

This page is little more than a placeholder, to be expanded in the future. Quantum Espresso has a procedure to calculate phonons as well, pretty much in the same way as Phonopy. After a regular pw.x calculation, the sequence ph.x ==> q2r.x ==> matdyn.x has to be followed. The latter produces an output file *.modes, which together with the input file for pw.x can be uploaded to the Interactive Phonon Visualizer at Materials Cloud. There you can select a phonon on the dispersion graph, and the corresponding motion of the atoms is displayed. A not always up to date manual on phonons with QE is available here.

If you feel like writing a step by step guide for performing such a calculation — for instance for the Si-lonsdaleite crystal as done here with Phonopy — then you are most welcome to do so. It’s an interesting exercise for you, and your guide will be helpful for future students. If you send it to me, I will upload it here.

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