Dear Prof.Kong How are you. Great appreciation to you for providing us codes freely.

As I calculated the dispersion of graphene(qusi-2D), the command fix phonon in lammps cannot work. But it is work for supercell of bulk silicon(3D)

The stucture of graphene supercell consist of 192 atoms with a 1.4nm thick vacuum layer.This supercell is obtained by expanding the unit cell of 4 atoms by 6*8*1,in which "1" denotes the thickness direction. 3D periodical boundary conditions are applied in MD by lammps. AIREBO potential is used to describe the interation in graphene.

The map file for dispersion calculation is produced by the code 'latgen',in which the lattice type option "7" is used. I already check the atom coordination and the atom ID by latgen to make sure that they are the same to those used in lammps.

However, the command fix phonon cannot work, exits with error message: mpirun noticed that process rank 1 with PID 16586 on node mez508.ust.hk exited on signal 11 (Segmentation fault).

Do you have comments and sugesstions? Attached please find the input files (in file and structure file) of lammps and map file by latgen for your test.

Best regards

Youdi

I noticed your report, but I am pretty busy recently. Will probably get back to you within two weeks. thanks.

It is fine. Many thanks for your endeavour.

Dear Prof.Kong Very sorry. We just find that the fix phonon cannot work well just because our server has some problems. This comand still works well for graphene.

very good.

Dear Prof.Kong I just use the input files above to calculate the dispersion curve of graphene but i got such a graph,can you help me?

And I tried to calculate the curve of a 2d squre lattice ,and compare the result with the book Solid State Theory by Zhengzhong Li. I'll be glad to see it be modified and become an example of FixPhonon,thank you !