MedeA MT
MedeA-MT predicts mechanical and thermomechanical properties of
high-performance alloys, hard materials, oxides and other more complex
materials.
MedeA-MT lets you determine elastic coefficients, Young’s moduli,
and shear moduli with unprecedented reliability and ease.
MedeA-MT uses VASP to compute the stress tensor and derives
elastic properties based on a multidimensional least square fit.
MedeA's Automated convergence allows to optimize VASP parameters for a
given
precision of the stress tensor.
Using MedeA Combi, a given set of computational parameters can
be applied to a
large set of input structures and elastic properties can be computed for the
whole set.
Key Features
-
Automated computation for any type of crystal structure including P1
-
Integrated
with the Ab Initio method VASP.
-
MedeA's job control manages compute intensive
applications in MT
-
Spreadsheet job submission (Combi) allows for large scale
screening
Calculated Properties
-
Elastic constants
-
Compliance matrix
-
Bulk and shear moduli for a polycrystalline sample (*)
-
Longitudinal and transverse velocities of sound (*)
-
Debye temperature (*)
-
Heat capacity and free energy (lattice contribution in
Debye approximation)
-
Thermal expansion coefficient (estimate within the Debye-Grüneisen
approximation)
Example 1 - Quartz
Quartz is one of the most common minerals in the earth’s
crust. It has a wide range of technological applications,
amongst them piezoelectrics and semiconductor devices. MedeA-MT
determines the elastic properties of SiO2 in good agreement
with experiments
.
  
Example 2 - Tourmaline
For complex structures such as the below tourmaline (Schorl),
the elastic constants can be readily determined using MedeA-MT.
The unit cell contains 8 species and 159 atoms. Using a parallel
compute cluster with 4 nodes (INTEL P-IV 2GHz or AMD 1800GHz)
such a calculation can be run overnight (~ 50 hours on a single
CPU).
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Remarks
(*) The theory of Voigt, Reuß and Hill is employed to derive
these properties.
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