hi

i am running scf calculation of PbSb two dimensional material. this is semiconductor. while running scf calculation i am getting this error.

  Self-consistent Calculation

     iteration #  1     ecut=    55.00 Ry     beta= 0.30      Davidson diagonalization with overlap      ethr =  1.00E-02,  avg # of iterations =  5.0

     negative rho (up, down):  2.999E-03 0.000E+00

     total cpu time spent up to now is        3.4 secs

     WARNING: integrated charge=    18.70000000, expected=    19.00000000

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%      Error in routine electrons (1):      charge is wrong: smearing is needed  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

     stopping ...

I am pasting scf.in file

&control         title = 'MoSe2' ,                  calculation = 'scf' ,                 restart_mode = 'from_scratch' ,                     outdir='/home2/oth/kk1469/scratch/Sb',                   pseudo_dir = '.' ,                       prefix = 'BN_gra' ,                    verbosity = 'high'                   wf_collect = .true.,  /

&system               ibrav = 4,                              A =4.53 ,                            B =4.53,                            C = 20,                        cosAB = -0.5 ,                        cosAC = 0.0 ,                        cosBC = 0.0 ,                          nat = 2,                         ntyp = 2,                      ecutwfc = 55 ,                      ecutrho = 550 ,

 / &ELECTRONS         mixing_mode = 'plain' ,                 mixing_beta = 0.2,                    conv_thr =  1.0d-6

/

ATOMIC_SPECIES Pb   207.2  Pb.pbe-mt_fhi.UPF Sb   121.760  Sb.pbe-mt_fhi.UPF ATOMIC_POSITIONS crystal  Pb    0.333333      0.666666      0.500000      Sb    0.666666      0.333333      0.500000            

K_POINTS automatic 20 20  1   0 0 0

please help me out.