EPW Forum

Hi
I am trying to calculate the conductivity of a 2D phosphorene (4 atoms in the unit cell). In the epw1.in file, I have defined the projection keyword as
Proj(1) = `P:s;p`
But when I run the epw.x code, I am getting the following error

param_get_projection: too many projections defined
Error: examine the output/error file for details

I then changed the Proj(1) = `random`, and when I ran the code, the error changed to the following one.

kmesh_get_bvector: Not enough bvectors found
Error: examine the output/error file for details

Please. suggest how to solve this problem.

Thanks and regards
Showkat H Mir
IIT Kanpur, India

Hello,

Your projection needs to be consistent with your number of bands (nbndsub) and energy windows (if you are using the Wannier disentanglement).

For example
Proj(1) = `P:p` means that you will have 6 electrons (p-shell) times 4 atoms in your unit cell = 24 electrons which means that you need nbndsub=24 or 12 depending if you use SOC or not.

Best wishes,
Samuel

Dear Dr. Samuel Ponc
Thank you for your kind reply. The problem about the projections is solved now. However, now the error changes to the following one.

kmesh_get_bvector: Not enough bvectors found
Error: examine the output/error file for details

Kindly, help to solve this problem. For your convenience, the epw1.in file is pasted here.
Thanks and regards
Showkat H Mir
IIT Kanpur, India


shm
&inputepw
prefix = 'phos'
amass(1) = 30.79300
amass(2) = 30.79300
amass(3) = 30.79300
amass(4) = 30.79300
outdir = './'

elph = .true.
kmaps = .false.
epbwrite = .true.
epbread = .false.
epwwrite = .true.
epwread = .false.
etf_mem = 1

nbndsub = 12
nbndskip = 0

lifc = .true.
asr_typ = 'crystal'

wannierize = .true.
num_iter = 1500
iprint = 4
dis_win_max = 0
dis_froz_max= -4
Proj(1) = 'random'
wdata(1) = 'bands_plot = .true.'
wdata(2) = 'begin kpoint_path'
wdata(3) = 'Y 0.0 0.5 0.0 G 0.0 0.0 0.0 '
wdata(4) = 'G 0.0 0.0 0.0 X 0.5 0.0 0.0 '
wdata(5) = 'X 0.5 0.0 0.0 M 0.5 0.5 0.0 '
wdata(6) = 'M 0.5 0.5 0.0 G 0.0 0.0 0.0 '
wdata(7) = 'end kpoint_path'
wdata(8) = 'bands_plot_format = gnuplot'
wdata(9) = 'guiding_centres = .true.'
wdata(10) = 'dis_num_iter = 500'
wdata(11) = 'num_print_cycles = 10'
wdata(12) = 'dis_mix_ratio = 1.0'
wdata(13) = 'use_ws_distance = T'

elecselfen = .false.
phonselfen = .false.
a2f = .false.

fsthick = 1.2 ! eV
eptemp = 1 ! K
degaussw = 0.005 ! eV

dvscf_dir = './save'

band_plot = .true.
filkf = './LGX.txt'
filqf = './LGX.txt'

nk1 = 12
nk2 = 12
nk3 = 2
nq1 = 3
nq2 = 3
nq3 = 2
/
8
0.000000000000000 0.000000000000000 0.000000000000000
0.000000000000000 0.000000000000000 -0.833333333333333
0.000000000000000 0.239000023900002 0.000000000000000
0.000000000000000 0.239000023900002 -0.833333333333333
0.333333333333333 0.000000000000000 0.000000000000000
0.333333333333333 0.000000000000000 -0.833333333333333
0.333333333333333 0.239000023900002 0.000000000000000
0.333333333333333 0.239000023900002 -0.833333333333333