<div dir="ltr"><pre>Thank you for your answer. We prepared symmetry of the system <br>in the same way as you are proposing. All the calculations have <br>been performed using the following potential expansion in case.in2c:<br>
<br>TOT (TOT,FOR,QTL,EFG,FERMI)<br> -9.0 8.0 0.50 0.05 EMIN, NE, ESEPERMIN, ESEPER0<br>TETRA 0.000 (GAUSS,ROOT,TEMP,TETRA,ALL eval)<br> 0 0 1 0 2 0 3 0 3 3 4 0 4 3 5 0 5 3 6 0 6 3 6 6<br>
20.00 GMAX<br><i></i><br>I think that the local symmetry we have used is OK. What do you think?<br>Best,<br>Martin Gmitra<br><br><br><br>Most likely this is a "symmetry" problem.<br><br>One cannot put the graphene sheet at an arbitrary z-position. Remember, <br>
adding an E-field means that we change the Coulomb-potential.<br>In order to keep periodicity, we use a zig-zag potential and of course <br>it does NOT make sense to put an atom at the position of the "kink"<br>
(z=0 or 0.5).<br><br>Of course when one adds an E-field along the z-direction, the mirror<br>symmetry within the graphene plane has gone. Thus it is essential to <br>have this fact reflected in the local symmetry (eg. you need a LM=1 0<br>
term for the E-field, which is normally absent for a single sheet).<br><br>I'd recommend to setup the struct file with 2 graphene layers (at z=0 <br>and 0.25), but one should contain eg. B atoms instead of C. After <br>
symmetry detection, remove the B-sheet (at z=0).<br><br>Martin Gmitra schrieb:<br>><i> Dear Wien2k users,<br></i>><i> <br></i>><i> We are running Wien2k 08.2 version on IBM AIX v 5.3 system (Uni Leoben). <br></i>><i> We are interested in effects of an external<br>
</i>><i> electric field on splitting in the graphene. We have recovered 24 micro <br></i>><i> eV splitting due to intrinsic spin-orbit interaction<br></i>><i> in the K-point. Setting up a ramp potential of rather huge amplitudes <br>
</i>><i> (1000 Ry/20A) has no effect on the splitting at all.<br></i>><i> I have not found relevant discussion in mailing list. Therefore, I would <br></i>><i> like to share my problem with you.<br></i>><i> <br>
</i>><i> The graphene sheet has been placed (i) in the quarter of the unit cell <br></i>><i> width (z=0.25) and complex calculations have<br></i>><i> run and; (ii) the sheet has been positioned in the origin (z=0) and real <br>
</i>><i> calculations have run with modified ramp<br></i>><i> potential in eramps.f within lapw0. The results we have obtained are <br></i>><i> almost the same - no change in the splitting.<br></i>><i> <br></i>><i> My question is:<br>
</i>><i> Is the present implementation of the external electric field suitable <br></i>><i> for monoatomic slab structures including<br></i>><i> spin-orbit coupling interaction?<br></i>><i> <br></i>><i> Many thanks,<br>
</i>><i> Martin Gmitra</i></pre></div>