Anharmonic properties of materials

d3q + thermal2

Anharmonic properties of materials

The code for anharmonic properties of materials is composed of two parts:

d3q

To compute fully ab-initio, the anharmonic third-order dynamical matrix and the three-body force constants. This code is very efficient, it uses the 2n+1 extension of density functional perturbation theory to compute the response of the system to three harmonic perturbations. It does not use expensive supercell and no range cutoff has to be imposed. It is tightly coupled with quantum-espresso, it supports norm-conserving pseudopotentials.

thermal2

A suite of codes to manipulate 2-body and 3-body force constants to study vibrational properties of materials:

These codes are loosely coupled with Quantum-ESPRESSO. They can natively use force constants from the ph and d3q codes, but can also import them from real-space thirorder and phonon3py codes.

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Example applications

Intrinsic phonon linewidth

Graphene intrinsic linewidth

Graphene intrinsic linewidth (dispersion) Graphene intrinsic linewidth (BZ)

Silicon intrinsic linewidth

Silicon intrinsic linewidth

Hyperacoustic wave attenuation

Temperature dependent attenuation (GaAs)

GaAs hyperacoustic waves attenuation

Final state decomposition

GaAs hyperacoustic scattering phase space

Thermal conductivity

Including finite-size effect, disorder, isotopes Bi2Se3 thermal conductivity

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Selection of Published works

If you have published a paper using the d3q or thermal2 software and would like to have it listed here, please contact me.

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