Thermodynamics of metals from first principles
Title: |
Thermodynamics of metals from first principles |
DNr: |
SNIC 2017/1-64 |
Project Type: |
SNIC Medium Compute |
Principal Investigator: |
Mattias Klintenberg <mattias@physics.uu.se> |
Affiliation: |
Uppsala universitet |
Duration: |
2017-02-28 – 2018-03-01 |
Classification: |
10304 |
Keywords: |
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Abstract
Density functional theory has become the standard method to predict
material properties from first principles, however it can in principle
only do that at 0 K temperature. Most materials are used at room
temperature, many at a lot higher. In order to calculate and predict
properties at those finite temperatures a full quantification of the
free energy surface of the material is required. Recently the available
computational power has risen to the level where it has become possible
to calculate all the relevant thermal excitation mechanisms, such as
electronic, harmonic and anharmonic vibrational, magnetic and point
defect, allowing for theoretical explanation of thermodynamic
properties such as heat capacity, thermal expansion coefficient or
phase stability. Several techniques such as "thermodynamic integration
based on Langevin dynamics" or "temperature-dependent effective
potential" have been used in order to reduce the complexity of these
calculations, however the accuracy and predictive power of those has
not been well established. In addition the "standard" implementation
difficulties associated with DFT such as selection of an
exchange-correlation functional, k-point sampling, choice of cutoff
energies, system size effects and so on further complicate the
situation. The aim of the project is to shed light on these matters by
systematically investigating the intricate details behind calculating
the free energy contributions, comparing different methods and
assessing their accuracy, limitations and advangates for different
metallic systems.