Green's function molecular dynamics (GFMD) code

This package implements the Green's function molecular dynamics, by introducing a LAMMPS fix, fix gfmd. It is used to evaluate the effective forces acting on an elastic half-space from the dynamical matrix.

This is an implementation of the method described in:

• C. Campana, M.H. Muser, Phys. Rev. B 74, 075420 (2006)
• L. Pastewka, T.A. Sharp, M.O. Robbins, Phys. Rev. B 86, 075459 (2012)

If you use this code, please cite these publications.

This code was used in the following publications:

• T.A. Sharp, L. Pastewka, M.O. Robbins, Phys. Rev. B 93, 121402(R) (2016)
• T.A. Sharp, L. Pastewka. V. Ligners, M.O. Robbins, Phys. Rev. B 96, 155436 (2017)
• A. Klemenz, A. Gola, M. Moseler, L. Pastewka, Appl. Phys. Lett. 112, 061601 (2018)
• J.M. Monti, M.O. Robbins, ACS Nano 14, 16997 (2020)

Dislaimer & Warning

The code is absolutely not idiot proof. If you plan to use it, please contact Lars Pastewka.

Build status

LAMMPS

You need LAMMPS patch_10Feb2021 or later to run this code. The sign of the FFT transform was flipped in this release. Please make sure all tests pass. Tests will catch any problem with the FFT.

Compiling this package along with LAMMPS requires the FFT3d wrappers from the kspace package of LAMMPS to be included. Please configure lammps with the MANYBODY, KSPACE and EXTRA-PAIR packages.

You should also append 'user-gfmd' to the 'PACKUSER' variable in the file of src/Makefile before invoke make yes-user. Note that make yes-user-gfmd does not work if used with the USER-CUDA package. If used with USER-CUDA, go into the USER-GFMD directory and execute sh Install.sh 1 manually.

Functionality beyond pair potentials will be included soon.

Installation

Note that we do not at present support CMake. A typical installation would look like this (in the LAMMPS src directory):

git clone https://github.com/Atomistica/user-gfmd.git USER-GFMD
make yes-extra-pair
make yes-manybody
make yes-kspace
make yes-user-gfmd
make fftw

Testing

There are two separate testing frameworks:

1. Unittests are separate from the LAMMPS executable and use Google Test v1.6.0. To compile type make unittests in the USER-GFMD directory. Then execute the "unittests" binary.

2. Compound tests run LAMMPS and check the output. To run these tests change to the tests subdirectory and run the run_test.sh executable with the path to the LAMMPS binary as the only argument.