Hi, venkatesh
Thanks for your immediate reply.
Imagine sending an electron with energy within the gap (in the case of
1x1x1 primitive cell) from vacuum towards the Au(111) surface (this
surface is perpendicular to [111] direction), the electron cannot
propagate inside the crystal and must be reflected backwards. Further,
if the energy of incoming electron is below the vacuum level (i.e., work
function), the electron cannot escape and is therefore confined. Now if
we switch to the case of 2x2x2 primitive cell, then we get the opposite
conclusion: the electron won't be confined! I suppose this is apparently
not the case.
On 09/07/2013 09:53 PM, venkatesh chandragiri wrote:
Hi,
In 2x2x2 cell, the band folding effects in a Brillouin Zone plays a
role on the arrangement of band structure due to increased cell
sizes...this may give clue to explain the absent of gap in 2x2x2 cell....
venkatesh.
On Sat, Sep 7, 2013 at 6:58 PM, Huang Bing <[email protected]
<mailto:[email protected]>> wrote:
Hi,
I'm using Siesta to calculate band structure of bulk gold. It's
expected to find one relative band gap (in which fermi level lies.
PS: this gap supports an occupied Shockley surface state) along GL
line (corresponding to [111] direction) in reciprocal space. I did
find one when setting the cell size to 1x1x1 (primitive cell
containing only one atom), but failed when setting cell size to
2x2x2 (primitive cell containing 8 atoms), see the attachment for
detail. I don't quite understand why the relative gap vanish near
fermi level, one consequence of which seems to be the
disappearance of the previously-mentioned Shockley surface state.
Can anyone explain this?
--
Ch. Venkatesh,
C/o. Prof. V. Srinivas,
Department of Physics & Meteorology,
IIT Kharagpur.
ph: +919445909693
