[gpaw-users] analysis mode in transport calculations

[Sylvain Tricot]

Dear gpaw-users,

I am currently working with version 0.9.1.10509 to compute transport
transmission coefficient maps on magnetic tri-layers structures
(Fe(001) 4 layers /Au(001) 2 layers /Fe(001) 4 layers).
Calculations are fine for now at no bias voltage (I used non_sc=True).
However, I would like to achieve a dense k-point sampling to improve the map
resolution. Following the website informations, I set the "analysis_mode"
parameter to True in the calculator along with more "kpts" and called
the "analysis(1)" function. But GPAW complains about not finding any 
"bias_data1" file.

Am I doing something wrong ? What is the best way to achieve dense 
k-point sampling ?

Thanks in advance for your help.
Regards,

Here are the calculator parameters and the stderr output.
(the device is composed of 10 atoms. The first 2 and the last 2 are the 
principal layers)


################################################################################
# Calculator
################################################################################
t = Transport(\
     h=0.22,\
     xc='LDA',\
     basis='dzp',\
     kpts=(2,2,1),\
         parallel={'domain':(1,1,1)},\
     occupations=FermiDirac(width=0.2, fixmagmom=False),\
     mode='lcao',\
         alpha=0.1,\
     spinpol=True,\
         beta_guess=0.08,
         extra_density=True,
     poissonsolver=PoissonSolver(nn=2, relax='GS', eps=2e-12),\
     txt='-',\
     #mixer=MixerSum(0.05, 5, weight=100.0),\
         mixer=MixerDif(beta=0.07, nmaxold=5, weight=100.0, beta_m=0.09, 
nmaxold_m=5, weight_m=100.0),
     maxiter=2000,\
     pl_atoms=[pl1, pl2],\
     pl_cells=[pl_cell1, pl_cell2],\
     pl_kpts=(2,2,11),\
         fixed_boundary=False,\
     non_sc=True)
system.set_calculator(t)
t.calculate_iv(v_limit=0.00000, num_v=1, start=0)

# More k-points
t = Transport(\
     h=0.22,\
     xc='LDA',\
     basis='dzp',\
     kpts=(6,6,1),\
         parallel={'domain':(1,1,1)},\
     occupations=FermiDirac(width=0.2, fixmagmom=False),\
     mode='lcao',\
         alpha=0.1,\
     spinpol=True,\
         beta_guess=0.08,
         extra_density=True,
     poissonsolver=PoissonSolver(nn=2, relax='GS', eps=2e-12),\
     txt='-',\
     #mixer=MixerSum(0.05, 5, weight=100.0),\
         mixer=MixerDif(beta=0.07, nmaxold=5, weight=100.0, beta_m=0.09, 
nmaxold_m=5, weight_m=100.0),
     maxiter=2000,\
     pl_atoms=[pl1, pl2],\
     pl_cells=[pl_cell1, pl_cell2],\
     pl_kpts=(6,6,11),\
         fixed_boundary=False,\
         analysis_mode = True,\
         analysis_data_list=['tc'],
     non_sc=True)
system.set_calculator(t)
t.analysis(1)

################################################################################
# GPAW output error
################################################################################

Traceback (most recent call last):
   File "./FeAuFe.py", line 177, in <module>
     t.analysis(1)
   File "/home/sylvain/gpaw/gpaw/transport/calculator.py", line 2644, in 
analysis
     fd = file('bias_data' + str(i + 1), 'r')
IOError: [Errno 2] No such file or directory: 'bias_data1'
GPAW CLEANUP (node 0): <type 'exceptions.IOError'> occurred. Calling 
MPI_Abort!



-- 
Sylvain Tricot
Ingénieur de Recherche
Institut de Physique de Rennes - UMR 6251
Département Matériaux/Nanosciences
Université de Rennes I
Campus de Beaulieu
Bat 11E
35042 Rennes Cedex - France

tel: +33 (0)2 23 23 69 06