[Pw_forum] Problems calculating barriers of metal-metal interfaces

[Dae Kwang Jun]

Dear all,

I am trying to obtain the "Schottky barrier heights" (or their equivalent)
of metal-metal interfaces using the potential line up method. From my
knowledge, the "Schottky barrier" should be nearly 0 eV for all metals.
However, so far I am obtaining values higher than 0.2 eV. In other cases,
the calculation fails to converge even if electron_maxtep = 200. Here is
the input file for an Al-Ag interface superlattice with no vacuum in the
superlattice. This input fails to converge in the first scf cycle even
after electron_maxstep= 200. Most of the input that I have tried is similar
to this one. What am I doing wrong ? I would appreciate any feedback.


&CONTROL
calculation = 'vc-relax'
restart_mode = 'from_scratch'
tstress = .true.
tprnfor = .true.
outdir = '/home/files/metal-metal'
pseudo_dir = '/home/espresso-5.4.0/pseudo'
prefix = '001_6x6_Al-Ag'
nstep = 100
/
&SYSTEM
ibrav = 6
a = 4.04
c = 48.36
ecutwfc = 40
ecutrho = 400
degauss = 0.03
ntyp = 2
nat = 48
nbnd = 230
/
&ELECTRONS
electron_maxstep = 200
mixing_mode = 'local-TF'
diagonalization = 'david'
conv_thr = 1.D-7
mixing_beta = 0.2
/
&IONS
/
&CELL
/
ATOMIC_SPECIES
Al  27   Al.pbe-n-rrkjus_psl.0.1.UPF
Ag  108  Ag.pbe-dn-rrkjus_psl.0.1.UPF
ATOMIC_POSITIONS {angstrom}
Al    0.000000    0.000000    0.000000
Al    0.000000    2.020000    2.020000
Al    2.020000    0.000000    2.020000
Al    2.020000    2.020000    0.000000
Al    0.000000    0.000000    4.040000
Al    0.000000    2.020000    6.060000
Al    2.020000    0.000000    6.060000
Al    2.020000    2.020000    4.040000
Al    0.000000    0.000000    8.080000
Al    0.000000    2.020000   10.100000
Al    2.020000    0.000000   10.100000
Al    2.020000    2.020000    8.080000
Al    0.000000    0.000000   12.120000
Al    0.000000    2.020000   14.139999
Al    2.020000    0.000000   14.139999
Al    2.020000    2.020000   12.120000
Al    0.000000    0.000000   16.160000
Al    0.000000    2.020000   18.180000
Al    2.020000    0.000000   18.180000
Al    2.020000    2.020000   16.160000
Al    0.000000    0.000000   20.200001
Al    0.000000    2.020000   22.220001
Al    2.020000    0.000000   22.220001
Al    2.020000    2.020000   20.200001
Ag    0.000000    0.000000   24.480000
Ag    0.000000    2.040000   26.520000
Ag    2.040000    0.000000   26.520000
Ag    2.040000    2.040000   24.480000
Ag    0.000000    0.000000   28.559999
Ag    0.000000    2.040000   30.599998
Ag    2.040000    0.000000   30.599998
Ag    2.040000    2.040000   28.559999
Ag    0.000000    0.000000   32.639999
Ag    0.000000    2.040000   34.680000
Ag    2.040000    0.000000   34.680000
Ag    2.040000    2.040000   32.639999
Ag    0.000000    0.000000   36.720001
Ag    0.000000    2.040000   38.760002
Ag    2.040000    0.000000   38.760002
Ag    2.040000    2.040000   36.720001
Ag    0.000000    0.000000   40.799999
Ag    0.000000    2.040000   42.840000
Ag    2.040000    0.000000   42.840000
Ag    2.040000    2.040000   40.799999
Ag    0.000000    0.000000   44.879997
Ag    0.000000    2.040000   46.919998
Ag    2.040000    0.000000   46.919998
Ag    2.040000    2.040000   44.879997
K_POINTS {automatic}
8 8 2 0 0 0
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