Germanane monolayerd

[danial]

Dear All

I would like to build the unit cell of Germanane from Germanium but i have some small problem that I couldn't build it.
it would be great if help me how can create unit cell and single layer Germanium(germanane).

I really appreciate all of you in advance.

[Umberto Martinez]

What kind of problem did you have?

please refer to the tutorial How to create a crystal structure with the Crystal Builder

[danial]

Thanks so much for your reply....indeed  have a problem to create single layer structure and unit cell of Germanium that we know it as a Germanane. again really appreciate your kind response.

sincerely

[zh]

1. Follow the tutorial indicated in the last reply by Umberto Martinez  to create the crystal structure of beta-Ga₂Ge;
2. Remove the all Ga atoms in the crystal structure obtained of the 1st step;
3. Remove two layers of Ge atoms in the resulting structure of the 2nd step;
3. According to the structure of germanane, add hydrogen atoms on the top of the Ge atoms in the the upper layer, add hydrogen atoms just below the Ge atoms in the bottom layer;
4. Do a geometry optimization for the in-plane lattice constants and atomic coordinates in the resulting structure of the 3rd step.

The atomic coordinates and lattice constants of beta-GaGe2 can be found in the following article:
Journal of Solid State Chemistry, Volume 180, Issue 5, May 2007, Pages 1575–1581,
Synthesis, structure and electronic structure of a new polymorph of CaGe2
  Paul H. Tobash,    Svilen Bobev
http://www.sciencedirect.com/science/article/pii/S0022459607001004

[danial]

first of all thanks so much for your kind help.

I did it but  have some problem,

1- on Crystal Builder in Space Group as paper mention we should use R-3m, when use R-3m we wouldn't find C6 for atom position so I try to use R3m instead of R-3m. which one is correct?

2- we should set lattice parameter, in the paper we have 2 value ''A'' and ''C'' but in Crystal Builder on Trigonal R-3m or R3m wanted '' A'' and a degree that doesn't mention in paper.(I think in paper mention R-3m as a atom position)

3- after making, (assume that R3m, A: 3.98, degree= 90) repeat my unit cell but didn't reach honey structure of Germanane.

sincerely yours

[danial]

it would be great if someone help me.!

Thanks.

[zh]

first of all thanks so much for your kind help.

I did it but  have some problem,

1- on Crystal Builder in Space Group as paper mention we should use R-3m, when use R-3m we wouldn't find C6 for atom position so I try to use R3m instead of R-3m. which one is correct?

2- we should set lattice parameter, in the paper we have 2 value ''A'' and ''C'' but in Crystal Builder on Trigonal R-3m or R3m wanted '' A'' and a degree that doesn't mention in paper.(I think in paper mention R-3m as a atom position)

3- after making, (assume that R3m, A: 3.98, degree= 90) repeat my unit cell but didn't reach honey structure of Germanane.

sincerely yours

1. When you use "Crystal Builder" to create the crystal structure of beta-GaGe2 according to the information of "Journal of Solid State Chemistry, Volume 180, Issue 5, May 2007, Pages 1575–1581", you should choose the space group of " 166(R-3m) hexagonal" in the "Rhombohedral/Trigonal" option.
2. Then you can enter the values for the lattice constants "a" and "c", and add the atomic coordinates for Ca, Ge1, and Ge2  atoms with "6c" Wyckoff position.

[zh]

The following script file provides an initial structure for GeH monolayer, which is constructed by removing Ga atoms and Ge atoms in the crystal structure of beta-CaGe2 and by adding hydrogen atoms.

# Set up lattice
lattice = Hexagonal(3.9872*Angstrom, 30.583*Angstrom)

# Define elements
elements = [Germanium, Germanium, Hydrogen, Hydrogen]

# Define coordinates
fractional_coordinates = [[ 0.66666667,  0.33333333,  0.51798333],
                          [ 0.33333333,  0.66666667,  0.48201667],
                          [ 0.60134218,  0.28773871,  0.56743569],
                          [ 0.28773871,  0.60134218,  0.43256431]]

# Set up configuration
bulk_configuration = BulkConfiguration(
    bravais_lattice=lattice,
    elements=elements,
    fractional_coordinates=fractional_coordinates
    )

To a proper structure of monolayer GeH, one must optimize this initial structure for the in-plane lattice constant and atomic coordinates.

[danial]

really I don't know how can I appreciate you for your effort and kindness ..
I hope I can compensate your kindness.
Thank you so so much.