<div dir="ltr">Hello,<div style> I am trying to study the H/LiF(001) system, my first insulating surface. When I calculate the energy as a function of the H-LiF surface I obtain an odd shoulder around 5 bohr (see figure attached). I am considering an 8 layer slab, around 30 bohr of vacuum between slabs, a sqrt(2)xsqrt(2) surface cell, pbe rrkjus US pseudopotentials for all three elements with Li semicore electrons included. Is this behavior expected for an ionic insulating surface? Or is there a problem with my input file? I am setting:</div>
<div style><div><br></div><div>&control</div><div> prefix = 'F',</div><div> outdir = '/home/myoutdir',</div><div> pseudo_dir = '/home/mypseudo',</div><div> calculation = 'scf',</div>
<div> lkpoint_dir = .false.,</div><div> verbosity = 'high',</div><div> nstep = 1,</div><div>/</div></div><div style><div>&system</div><div> ibrav = 8,</div><div> celldm(1) = 7.6899999999999995,</div>
<div> celldm(2) = 1.0000000000000000,</div><div> celldm(3) = 7.5000000000000009,</div><div> nat = 33,</div><div> ntyp = 3,</div><div> ecutwfc = 100,</div><div> ecutrho = 500,</div><div>
occupations = 'smearing',</div><div> smearing = 'gaussian',</div><div> degauss = 0.0001,</div><div> nspin = 2,</div><div> starting_magnetization(1) = 0.</div><div> starting_magnetization(2) = 0.</div>
<div> starting_magnetization(3) = 1.</div><div>/</div><div>&electrons</div><div> conv_thr = 1.d-6,</div><div> diagonalization = 'cg',</div><div> mixing_mode = 'plain',</div><div> mixing_beta = 0.7D0,</div>
<div>/</div><div>ATOMIC_SPECIES</div><div> F 18.9984032 F.pbe-n-rrkjus_psl.0.1.UPF</div><div> Li 6.941 Li.pbe-s-rrkjus_psl.0.2.1.UPF</div><div> H 1.00794 H.pbe-rrkjus_psl.0.1.UPF</div><div><div>ATOMIC_POSITIONS crystal</div>
<div> H 0 0 0.5013437 0 0 0</div><div> F 0.00 0.00 0.46666667 0 0 0</div><div> Li 0.50 0.00 0.46666667 0 0 0</div><div> Li 0.00 0.50 0.46666667 0 0 0</div><div> F 0.50 0.50 0.46666667 0 0 0</div>
<div> Li 0.00 0.00 0.40000000 0 0 0</div><div> F 0.50 0.00 0.40000000 0 0 0</div><div> F 0.00 0.50 0.40000000 0 0 0</div><div> Li 0.50 0.50 0.40000000 0 0 0</div><div> F 0.00 0.00 0.33333333 0 0 0</div>
<div> Li 0.50 0.00 0.33333333 0 0 0</div><div> Li 0.00 0.50 0.33333333 0 0 0</div><div> F 0.50 0.50 0.33333333 0 0 0</div><div> Li 0.00 0.00 0.26666667 0 0 0</div><div> F 0.50 0.00 0.26666667 0 0 0</div>
<div> F 0.00 0.50 0.26666667 0 0 0</div><div> Li 0.50 0.50 0.26666667 0 0 0</div><div> F 0.00 0.00 0.20000000 0 0 0</div><div> Li 0.50 0.00 0.20000000 0 0 0</div><div> Li 0.00 0.50 0.20000000 0 0 0</div>
<div> F 0.50 0.50 0.20000000 0 0 0</div><div> Li 0.00 0.00 0.13333333 0 0 0</div><div> F 0.50 0.00 0.13333333 0 0 0</div><div> F 0.00 0.50 0.13333333 0 0 0</div><div> Li 0.50 0.50 0.13333333 0 0 0</div>
<div> F 0.00 0.00 0.06666667 0 0 0</div><div> Li 0.50 0.00 0.06666667 0 0 0</div><div> Li 0.00 0.50 0.06666667 0 0 0</div><div> F 0.50 0.50 0.06666667 0 0 0</div><div> Li 0.00 0.00 0.00000000 0 0 0</div>
<div> F 0.50 0.00 0.00000000 0 0 0</div><div> F 0.00 0.50 0.00000000 0 0 0</div><div> Li 0.50 0.50 0.00000000 0 0 0</div><div>K_POINTS automatic</div><div> 3 3 1 1 1 1</div></div><div><br></div><div style>
For testing purposes, I am using an unrelaxed LiF surface.</div><div style><br></div><div style>Any help and/or suggestion will be greatly appreciated. I myself am quite at a loss...:-( </div><div style><br></div><div style>
Gisela.</div><div style>Surface Physics Group</div><div style>Centro Atómico Bariloche</div><div style>Argentina</div><div style><br></div></div></div>