[Wien] Metallic Behavior of Si 100 layer

[delamora]

One additional thing; the surface Si layer is closer to the second Si layer, 2.30A, compared to the distance between the two internal Si layers, 2.38A. This may be the reason for the "surface conductivity".
This may be caused by the lack of the second H atom that would shorten the Si-Si bond at the surface...

________________________________________
De: wien-bounces at zeus.theochem.tuwien.ac.at <wien-bounces at zeus.theochem.tuwien.ac.at> en nombre de Oleg Rubel <orubel at lakeheadu.ca>
Enviado: domingo, 19 de julio de 2015 04:08 p. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Metallic Behavior of Si 100 layer

In addition to that: The surface is truncated in a way that each Si has *two* dangling bonds. Thus two H-atoms per one Si at the surface are needed to passivate dangling bonds. I enclosed a sketch (I hope it will come through) where the proposed changes are shown for one Si atom. Note that the H-atoms are oriented to keep tetrahedral coordination of Si.

I hope it will help
Oleg

>> On Jul 19, 2015, at 3:00 PM, delamora <delamora at unam.mx> wrote:
>>
>> Sorry, I wanted to say "symmetrize"
>>
>>
>> De: wien-bounces at zeus.theochem.tuwien.ac.at <wien-bounces at zeus.theochem.tuwien.ac.at> en nombre de delamora <delamora at unam.mx>
>> Enviado: domingo, 19 de julio de 2015 02:56 p. m.
>> Para: A Mailing list for WIEN2k users
>> Asunto: Re: [Wien] Metallic Behavior of Si 100 layer
>>
>> If you systematize your system you will have a much simpler problem;
>> Here in the SiH100.struct I moved the central plane to 0 0 1/2, then I averaged the positions of the atoms above the plane and the equivalent atom below this plane.
>> After this "sgroup" changed the structure to a simpler and more symmetric one.
>>
>> Now, here you have 4 Si layers, maybe you can grow the thickness of your system.
>>
>> Pablo
>>
>>
>> De: wien-bounces at zeus.theochem.tuwien.ac.at <wien-bounces at zeus.theochem.tuwien.ac.at> en nombre de Muhammad Sajjad <sajjadpu at gmail.com>
>> Enviado: domingo, 19 de julio de 2015 06:16 a. m.
>> Para: A Mailing list for WIEN2k users
>> Asunto: Re: [Wien] Metallic Behavior of Si 100 layer
>>
>> Thank you Oleg, the structure file is attached herewith.
>>
>> On Sun, Jul 19, 2015 at 3:05 PM, Oleg Rubel <orubel at lakeheadu.ca> wrote:
>> Including the  structure file would be helpful.
>> Oleg
>> On Jul 19, 2015 12:24 AM, "Muhammad Sajjad" <sajjadpu at gmail.com> wrote:
>> Dear User
>> After relaxation, the Si 100 layer saturated with H  is behaving like a metal. I am unable to find its reason or some wrong approach followed in my calculations. Could you please guide me?
>>
>> Many thanks
>> Muhammad Sajjad
>>
>>
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>>
>> --
>> Kind Regards
>> Muhammad Sajjad
>> Post Doctoral Fellow
>> KAUST, KSA.
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> <Si-surface.pdf>

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