[Wien] Question about the sign (orientation) of the Efield

[Coriolan TIUSAN]

Dear Wien2k users,

I have a question concerning the direction of the Electric field applied 
using the zig-zag potential (via case.in0).

Following the paper of Stahn et al, PHYSICAL REVIEW B, VOLUME 63, 165205 
(2001), Page 7, Fig. 7 one can see that:

- corresponding to the descending Vext ramp one has a negative  E field 
(with respect to the direction of the supercell c axis).

- vice-versa, correspondig to the ascending Vext ramp one has a pozitive 
E field.

This representation is a bit counter-intuitive, because from E=-dV/dz 
one would expect opposite E field sign...

However, analysis of results some calculations I have performed for E 
field applied to a supercell with Au3ML/Fe5ML/MgO3ML/vaccum(half of 
cell) would confirm the E field convention from the paper of Stahn.

Is the same convention implemented in Wien2k?

Additionally, could you provide some clarification about the E field 
sign in wien2k (with respect to the z axis of the supercell), in the 
user guide (lapw0 section) the E field direction is not discussed.

Everithing about the Vext amplitude is clear: moreover, from 
case.output0 one can extract and plot the voltage ramp, but still... no 
ideea about EFIELD direction (sign).

With thanks in advance,

C. Tiusan


-- 
__________________________________________________________________
|       Prof. Dr. Eng. Habil. Coriolan Viorel TIUSAN              |
|---------------------------------------------------------------  |
|                                                                 |
| Department of Physics and Chemistry                             |
| Technical University of Cluj-Napoca                             |
|                                                                 |
| Center of Superconductivity, Spintronics and Surface Science    |
| Str. Memorandumului No. 28, RO-400114 Cluj-Napoca, ROMANIA      |
|                                                                 |
|       Tel: +40-264-401-465 Fax: +40-264-592-055                 |
|                Cell: +40-732-893-750                            |
|       e-mail: coriolan.tiusan at phys.utcluj.ro                    |
|       web: http://www.c4s.utcluj.ro/                            |
|_______________________________________________________________  |
|                         	                                  |
|  Senior Researcher                                              |
|  National Center of Scientific Research - FRANCE                |
|  e-mail: coriolan.tiusan at ijl.nancy-universite.fr                |
|  web: http://www.c4s.utcluj.ro/webperso/tiusan/welcome.html     |
|_________________________________________________________________|