Dear Bin,
I can't check your input thoroughly as I'm on vacation, but there are
2 things I noticed:
1. The doping seems quite high - maybe you're close to the van Hove
singularity which could explain problems. Can you try with less doping
and then - if this converges - increase the doping till you get
problems? And plot the total potential - maybe the charge is already
spilling into the vacuum?! This is connected to the second problem:
2. It can help if you "hide" the gate in the barrier. A typical setup
I used recently:
zgate = 0.589,
emaxpos = 0.59,
eopreg = 0.01,
block = .true.,
block_1 = 0.50,
block_2 = 0.60,
block_height = 2.50,
and the system is below 0.5... E.g. for your case, try
zgate = 0.1311111
block = .true.
block_1 = 0.13
block_2 = 0.23
block_height = 2.5
edir = 3
emaxpos = 0.13
eopreg = 0.01
The barrier starts with the dipole correction and the gate is right
behind the dipole... Compare with Fig. 2 of the PRB (2014). Also note
that 2.5 Ry for the barrier height is an arbitrarily chosen value - I
noticed other people now also use 2.5 Ry even if 2 Ry or even 1.5 Ry
should be enough. Yet, the higher the doping, the higher the dipole
correction the higher the barrier (if you "hide" everything in the
barrier)...
Regards & Greeting from the lake Garda in Italy
Thomas
Zitat von Bin Shao <bshao...@outlook.com>:
Dear all,
I would like to learn how to set up calculations of field-effect
configuration in quantum espresso. I read the paper "T. Brumme, M.
Calandra, F. Mauri; PRB 89, 245406 (2014)." and started with
graphene as an example. The input file is as follows. During the scf
calculation, there are a lot of warnings like " c_bands: 1
eigenvalues not converged". And the calculation could not get
converged after 800 iterations, could anyone help me with the input
file? Thanks in advance!
Best regards,
Bin
========================================================================
&CONTROL
calculation = 'scf'
etot_conv_thr = 2.0000000000d-05
forc_conv_thr = 1.0000000000d-04
outdir = './out/'
prefix = 'aiida'
pseudo_dir = './pseudo/'
tprnfor = .true.
tstress = .true.
gate = .true.
dipfield = .true.
tefield = .true.
verbosity = 'high'
/
&SYSTEM
degauss = 0.02
ecutrho = 500
ecutwfc = 45
ibrav = 0
nat = 2
ntyp = 1
occupations = 'smearing'
smearing = 'cold'
tot_charge = -0.2
zgate = 0.1
block = .true.
block_1 = 0.13
block_2 = 0.23
block_height = 2.5
edir = 3
emaxpos = 0.005
eopreg = 0.01
/
&ELECTRONS
conv_thr = 1.0000000000d-9
electron_maxstep = 800
mixing_beta = 0.4
mixing_mode = 'local-TF'
/
ATOMIC_SPECIES
C 12.011 C.pbe-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS crystal
C 0.0000000000 0.0000000000 0.3500000000
C 0.3333333000 0.6666667000 0.3500000000
K_POINTS automatic
65 65 1 0 0 0
CELL_PARAMETERS angstrom
2.4638000000 0.0000000000 0.0000000000
-1.2319000000 2.1336508000 0.0000000000
0.0000000000 0.0000000000 35.0000000000
======================================================================================
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