Yb:YAG crystal

[alberto]

Hello cp2k users,
I want to study a crystal of YAG (Y3Al5O12) doped with Yb3 +.

The cation Yb(III) tends to replace Y(III), since the two cations have very similar ionic radii.
Hence Yb (III)   occupies the dodecahedral sites of the crystal.
However, in the scientific literature it is hypothesized that a small percentage of doping Yb(III)   can occupy the octahedral sites, i.e. Yb(III)   replaces Al(III)   cations.
This hypothesis is supported by recent spectroscopic evidence. The experimental data are present in the article https://doi.org/10.1016/j.jssc.2022.123577

    

I would like to succeed or evaluate the splitting of the f orbitals of the Yb3 + ion when it occupies the octahedral site of the crystal.

Is there any way I could deal with this kind of problem on CP2K?

I would have thought of bad structure or pdos calculations to extract this information (although I think it is not a simple thing and maybe it is not the correct way to go).
I have no experience with this type of calculations, but if you have suggestions I try to perform them following the guidelines of the exercise https://www.cp2k.org/exercises:2017_uzh_cmest:band.

Thanks for your help

Alberto

[Victor Volkov]

Hello:

I wonder if this is the structure you would have to adopt

https://materialsproject.org/materials/mp-3050?formula=Y3Al5O12

Victor

[alberto]

Thanks Victor,

I have already done some calculations starting from that structure.
I replaced an octahedral Al(III) cation in the cell with Yb(III) and optimized the structure with PBEsol and basis set MOLOPT to see how the structure was distorted.
But now I would like to find a way to evaluate the splitting of the f orbitals of Yb(III) when it is in that site in the crystal.

Alberto 

[Victor Volkov]

According to my experience,

when one calls for PDOS,

CP2K prints each type of state for each type of atom in a separate column.

Therefore, I think, if you have one Yb3+ substitution, you would be able to read energies of its s, p, d and f electron states

according to the definition of the basis you use.

Victor  

[alberto]

Thanks for your advice.
So I try to do a PDOS calculation.
Do you think the DZVP-MOLOPT-SR-GTH basis set for Al, O, Y and Yb is a good basis?
I also thought of using the PBESOL hybrid base (in the manual I found this: HYB_GGA_XC_LC_WPBESOL_WHS which is the one with which I optimized the entire structure)

Alberto

[alberto]

*PBEsol hybrid functional

[Victor Volkov]

> Do you think the DZVP-MOLOPT-SR-GTH basis set for Al, O, Y and Yb is a good basis?

Dear Albert

I believe, to my humble opinion,

whatever variances you would study for Yb3+

would be curious.

Personally, I am curious:

in 1989, I had my first laser engineering with YAG and Phosphate Glass 50 cm rods

nano-pulsing once in 2 seconds to cool; the condensers were half meter.

"-)

Best.

Victor

 

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[alberto]

Dear Victor,
soon I will start to do some tests to see if I can calculate the splitting of the Yb (III) orbitals. This I need to justify the presence of a band in the spectrum of a Yb: YAG ceramic which could be due to the occupation of a small percentage of the Yb(III) cations of octahedral sites in the crystal.

I will keep you updated

Best

Alberto

[Victor Volkov]

Good luck, Alberto.

The attached pdf could be relevant.

Best

Victor

To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/5f085107-f57a-4dec-ac59-f4b2fc552a84n%40googlegroups.com.