[Pw_forum] semiconducting CNT/metallic CNT

[chengyu yang]

Thanks xirainbow, but when I changed the degauss to 0, the software said i
need to expand the value. I guess because there're Cu atoms in this system.
can anybody give me an direction?
The following are the script i used.

&CONTROL
                 calculation = 'scf' ,
                restart_mode = 'from_scratch' ,
                       prefix = '22' ,
 /
 &SYSTEM
                       ibrav = 6,celldm(1) =
21.764541128,celldm(3)=0.213765379
                         nat = 10,ntyp = 2,ecutwfc = 75 ,
                     occupations='smearing', smearing='gaussian', degauss=0
 /
&ELECTRONS
                    conv_thr = 1.0d-8 ,
                 mixing_beta = 0.7 ,
 /
ATOMIC_SPECIES
    C   12.01100  C.pz-vbc.UPF
    Cu  63.55     Cu.pz-d-rrkjus.UPF

ATOMIC_POSITIONS angstrom
  C        1.402181    -0.000000    -1.233916
  C        0.682146     1.225067    -1.233916
  C       -0.000000     1.402181    -0.000000
  C       -1.225067     0.682146    -0.000000
  C       -1.402181    -0.000000    -1.233916
  C       -0.682146    -1.225067    -1.233916
  C       -0.000000    -1.402181    -0.000000
  C        1.225067    -0.682146    -0.000000
  Cu       0            2.804362      0
  Cu      -1.402181     2.428648737   0


K_POINTS automatic
    1 1 5 0 0 0


2010/8/27 xirainbow <nkxirainbow at gmail.com>

> Dear Chengyu:
> For semiconductor, the degauss should be zero.
> That means the occupancy is 1.
>
>
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