Dear all

I have recalculated the elastic tensors with DFT, the input files is download from the Material project. I found the following tensors are incrrect: mp-21862 mp-5508 mp-975322 mp-1655 mp-86279 mp-1016904 mp-1018070 mp-21005 mp-1013564.

Waiting for your replay.

Best wishes

Thanks for the feedback!

Weâ€™ve noticted that some of the elastic tensors may be incorrect and we are working on recalculating these.

What do you mean by incorrect; can you elaborate by giving an example? Also how you did your calculations? I understand that you downloaded VASP inputs from the MP website, but what algorithm did you use to calculate the elastic tensor, the one implemented in VASP or the MP one implemented in atomate? I am asking because there may be differences between the results obtained from the two methods.

The calculations details for mp-1013564.

INCAR for opt:

ALGO = Fast

EDIFF = 1E-6

EDIFF = -1E-2

ENCUT = 520

IBRION = 2

ISIF = 3

ISPIN = 2

LASPH = True

LORBIT = 11

LREAL = Auto

LWAVE = False

MAGMOM = 5*0.6

NELM = 100

NSW = 99

PREC = Accurate

SIGMA = 0.05

POSCAR:

Sr3 Bi1 As1

1.0

5.880000 0.000000 0.000000

0.000000 5.880000 0.000000

0.000000 0.000000 5.880000

Sr Bi As

3 1 1

direct

0.000000 0.500000 0.500000 Sr

0.500000 0.000000 0.500000 Sr

0.500000 0.500000 0.000000 Sr

0.000000 0.000000 0.000000 Bi

0.500000 0.500000 0.500000 As

KPOINTS:

KPT-Resolved Value to Generate K-Mesh: 0.025

0

Gamma

7 7 7

0.0 0.0 0.0

POTCAR:

TITEL = PAW_PBE Sr_sv 07Sep2000

TITEL = PAW_PBE Bi_d 06Sep2000

TITEL = PAW_PBE As 22Sep2009

The strain stress method (Tutorials â€” vaspkit 1.3 documentation) is used for calculation with the help of vaspkit (Overview â€” vaspkit 1.3 documentation).

The INCAR for strain stress method:

ALGO = Fast

EDIFF = 1E-6

EDIFF = -1E-2

ENCUT = 520

IBRION = 2

ISIF = 2

ISPIN = 2

LASPH = True

LORBIT = 11

LREAL = Auto

LWAVE = False

MAGMOM = 5*0.6

NELM = 100

NSW = 99

PREC = Accurate

SIGMA = 0.05.

The applied strains are :-0.015 -0.010 -0.005 0.000 0.005 0.010 0.015.

This method is checked with IBRION=6 to calculate the elastic tensor.

Thanks for the detailed calculation info!

According to vaspkit: â€śConsidering that the energy-strain has less stress sensitivity than the stress-strain one, the former method has been implemented into the VASPKIT code.â€ť, I suppose you were using the energy-based methods rather than the stress-based method, right?

The results on MP were obtained using the stress-based method, and weâ€™ve found that â€śLREAL=AUTOâ€ť causes big issues for some of our calculations (we are switching to â€śLREAL=FALSEâ€ť). I am not sure whether this will be a problem for the energy-based method.

That being said, itâ€™s highly possible the results on MP are incorrect for the materials you listed. We have new calculations for them (not publicly available yet) and I am currently checking them. Will get back to you soon!

Thanks for your kind reply. The fact is that I used stress-based method, vaspkit provides two methods for calculation, they are stress-based and energy-based, respectively. I employed stress-based methods for calculation.I employed the GPU card for calculation, LREAL=AUTO has to be set. I am waiting for your calculaiton. Thanks.

For the listed materials, our new calculations have a large difference from the values in the production database. You are right, the current values in the production database are incorrect. Hope the new values match what youâ€™ve obtained. It would be great if you could do a comparison and let me know.

We are working to push the new calculations into the production database and hopefully we will soon correct these.

In below, format `raw`

means values in a frame of reference same as the structure (typically the ones directly obtained from VASP), and format `ieee_format`

means values transformed to a new frame of reference defined by IEEE (see Charting the complete elastic properties of inorganic crystalline compounds | Scientific Data). FYI, `mp-86279`

is not a valid material.

========================================

mp-21862

Format: raw

Production database:

[[759. 335. 335. 0. 0. 0.]

[335. 759. 335. 0. 0. 0.]

[335. 335. 759. 0. 0. 0.]

[ 0. 0. 0. 130. 0. 0.]

[ 0. 0. 0. 0. 130. 0.]

[ 0. 0. 0. 0. 0. 130.]]

New calculation:

[[754. 50. 50. 0. 0. 0.]

[ 50. 754. 50. 0. 0. 0.]

[ 50. 50. 754. 0. 0. 0.]

[ 0. 0. 0. 125. 0. 0.]

[ 0. 0. 0. 0. 125. 0.]

[ 0. 0. 0. 0. 0. 125.]]

Format: ieee_format

Production database:

[[759. 335. 335. 0. 0. 0.]

[335. 759. 335. 0. 0. 0.]

[335. 335. 759. 0. 0. 0.]

[ 0. 0. 0. 130. 0. 0.]

[ 0. 0. 0. 0. 130. 0.]

[ 0. 0. 0. 0. 0. 130.]]

New calculation:

[[754. 50. 50. 0. 0. 0.]

[ 50. 754. 50. 0. 0. 0.]

[ 50. 50. 754. 0. 0. 0.]

[ 0. 0. 0. 125. 0. 0.]

[ 0. 0. 0. 0. 125. 0.]

[ 0. 0. 0. 0. 0. 125.]]

========================================

mp-5508

Format: raw

Production database:

[[ 6.e+02 5.e+02 6.e+02 0.e+00 0.e+00 0.e+00]

[ 5.e+02 6.e+02 6.e+02 0.e+00 0.e+00 0.e+00]

[ 5.e+02 5.e+02 7.e+02 0.e+00 0.e+00 0.e+00]

[ 0.e+00 0.e+00 0.e+00 8.e+01 0.e+00 0.e+00]

[ 0.e+00 0.e+00 0.e+00 0.e+00 8.e+01 0.e+00]

[ 4.e-01 -4.e-01 0.e+00 0.e+00 0.e+00 4.e+01]]

New calculation:

[[2924. 1428. 1428. 0. 0. 0.]

[1428. 2924. 1428. 0. 0. 0.]

[1428. 1428. 2924. 0. 0. 0.]

[ 0. 0. 0. 590. 0. 0.]

[ 0. 0. 0. 0. 590. 0.]

[ 0. 0. 0. 0. 0. 590.]]

Format: ieee_format

Production database:

[[583. 498. 556. 0. 0. 0.]

[498. 583. 556. 0. 0. 0.]

[556. 556. 695. 0. 0. 0.]

[ 0. 0. 0. 79. 0. 0.]

[ 0. 0. 0. 0. 79. 0.]

[ 0. 0. 0. 0. 0. 42.]]

New calculation:

[[2924. 1428. 1428. 0. 0. 0.]

[1428. 2924. 1428. 0. 0. 0.]

[1428. 1428. 2924. 0. 0. 0.]

[ 0. 0. 0. 590. 0. 0.]

[ 0. 0. 0. 0. 590. 0.]

[ 0. 0. 0. 0. 0. 590.]]

========================================

mp-1655

Format: raw

Production database:

[[643. 497. 497. 0. 0. 0.]

[497. 643. 497. 0. 0. 0.]

[497. 497. 643. 0. 0. 0.]

[ 0. 0. 0. 116. 0. 0.]

[ 0. 0. 0. 0. 116. 0.]

[ 0. 0. 0. 0. 0. 116.]]

New calculation:

[[3318. 1933. 1933. 0. 0. 0.]

[1933. 3318. 1933. 0. 0. 0.]

[1933. 1933. 3318. 0. 0. 0.]

[ 0. 0. 0. 1094. 0. 0.]

[ 0. 0. 0. 0. 1094. 0.]

[ 0. 0. 0. 0. 0. 1094.]]

Format: ieee_format

Production database:

[[643. 497. 497. 0. 0. 0.]

[497. 643. 497. 0. 0. 0.]

[497. 497. 643. 0. 0. 0.]

[ 0. 0. 0. 116. 0. 0.]

[ 0. 0. 0. 0. 116. 0.]

[ 0. 0. 0. 0. 0. 116.]]

New calculation:

[[3318. 1933. 1933. 0. 0. 0.]

[1933. 3318. 1933. 0. 0. 0.]

[1933. 1933. 3318. 0. 0. 0.]

[ 0. 0. 0. 1094. 0. 0.]

[ 0. 0. 0. 0. 1094. 0.]

[ 0. 0. 0. 0. 0. 1094.]]

========================================

mp-1016904

Format: raw

Production database:

[[ 9.e+02 4.e+02 4.e+02 0.e+00 0.e+00 0.e+00]

[ 8.e+02 5.e+02 4.e+02 0.e+00 0.e+00 0.e+00]

[ 8.e+02 4.e+02 5.e+02 0.e+00 0.e+00 0.e+00]

[ 7.e+01 -7.e+01 -8.e-01 7.e+01 0.e+00 0.e+00]

[ 3.e+01 -4.e+01 -7.e-01 0.e+00 7.e+01 0.e+00]

[ 4.e+01 2.e+00 -3.e+01 0.e+00 0.e+00 7.e+01]]

New calculation:

[[5582. 1329. 1329. 0. 0. 0.]

[1329. 5582. 1329. 0. 0. 0.]

[1329. 1329. 5582. 0. 0. 0.]

[ 0. 0. 0. 1327. 0. 0.]

[ 0. 0. 0. 0. 1327. 0.]

[ 0. 0. 0. 0. 0. 1327.]]

Format: ieee_format

Production database:

[[656. 517. 533. 0. 0. 0.]

[517. 657. 533. 0. 0. 0.]

[533. 533. 697. 0. 0. 0.]

[ 0. 0. 0. 67. 0. 0.]

[ 0. 0. 0. 0. 67. 0.]

[ 0. 0. 0. 0. 0. 65.]]

New calculation:

[[5582. 1329. 1329. 0. 0. 0.]

[1329. 5582. 1329. 0. 0. 0.]

[1329. 1329. 5582. 0. 0. 0.]

[ 0. 0. 0. 1327. 0. 0.]

[ 0. 0. 0. 0. 1327. 0.]

[ 0. 0. 0. 0. 0. 1327.]]

========================================

mp-1018070

Format: raw

Production database:

[[605. 554. 554. 0. 0. 0.]

[554. 605. 554. 0. 0. 0.]

[554. 554. 605. 0. 0. 0.]

[ 0. 0. 0. 24. 0. 0.]

[ 0. 0. 0. 0. 24. 0.]

[ 0. 0. 0. 0. 0. 24.]]

New calculation:

[[2095. 713. 1261. 0. 0. 0.]

[ 713. 2095. 1261. 0. 0. 0.]

[1261. 1261. 2277. 0. 0. 0.]

[ 0. 0. 0. 790. 0. 0.]

[ 0. 0. 0. 0. 790. 0.]

[ 0. 0. 0. 0. 0. 643.]]

Format: ieee_format

Production database:

[[605. 554. 554. 0. 0. 0.]

[554. 605. 554. 0. 0. 0.]

[554. 554. 605. 0. 0. 0.]

[ 0. 0. 0. 24. 0. 0.]

[ 0. 0. 0. 0. 24. 0.]

[ 0. 0. 0. 0. 0. 24.]]

New calculation:

[[2095. 713. 1261. 0. 0. 0.]

[ 713. 2095. 1261. 0. 0. 0.]

[1261. 1261. 2277. 0. 0. 0.]

[ 0. 0. 0. 790. 0. 0.]

[ 0. 0. 0. 0. 790. 0.]

[ 0. 0. 0. 0. 0. 643.]]

========================================

mp-21005

Format: raw

Production database:

[[408. 368. 368. 0. 0. 0.]

[368. 408. 368. 0. 0. 0.]

[368. 368. 408. 0. 0. 0.]

[ 0. 0. 0. 42. 0. 0.]

[ 0. 0. 0. 0. 42. 0.]

[ 0. 0. 0. 0. 0. 42.]]

New calculation:

[[1607. 753. 483. 0. 0. 0.]

[ 753. 1545. 454. 0. 0. 0.]

[ 483. 454. 1054. 0. 0. 0.]

[ 0. 0. 0. 450. 0. 0.]

[ 0. 0. 0. 0. 450. 0.]

[ 0. 0. 0. 0. 0. 449.]]

Format: ieee_format

Production database:

[[408. 368. 368. 0. 0. 0.]

[368. 408. 368. 0. 0. 0.]

[368. 368. 408. 0. 0. 0.]

[ 0. 0. 0. 42. 0. 0.]

[ 0. 0. 0. 0. 42. 0.]

[ 0. 0. 0. 0. 0. 42.]]

New calculation:

[[1402. 564. 564. 0. 0. 0.]

[ 564. 1402. 564. 0. 0. 0.]

[ 564. 564. 1402. 0. 0. 0.]

[ 0. 0. 0. 450. 0. 0.]

[ 0. 0. 0. 0. 450. 0.]

[ 0. 0. 0. 0. 0. 450.]]

I have compared your results with mine. I found mp-1016904 has a large difference.

My tensor is

The INCAR for relaxion:

ALGO = Fast

EDIFF = 1E-8

EDIFF = -1E-3

ENCUT = 520

IBRION = 2

ISIF = 3

ISPIN = 2

LASPH = True

LDAU = True

LDAUJ = 0 0 0

LDAUL = 2 0 0

LDAUPRINT = 1

LDAUTYPE = 2

LDAUU = 3.25 0 0

LMAXMIX = 4

LORBIT = 11

LREAL = Auto

LWAVE = False

MAGMOM = 1*5.0 4*0.6

NELM = 100

NSW = 99

PREC = Accurate

SIGMA = 0.05

KPOINTS:

K-Spacing Value to Generate K-Mesh: 0.025

0

Gamma

10 10 10

0.0 0.0 0.0

POTCAR:

TITEL = PAW_PBE V_sv 02Aug2007

TITEL = PAW_PBE Cd 06Sep2000

TITEL = PAW_PBE O 08Apr2002

POSCAR:

V1 Cd1 O3

1.0

3.840124 0.000000 0.000000

0.000000 3.840124 0.000000

0.000000 0.000000 3.840124

V Cd O

1 1 3

direct

0.500000 0.500000 0.500000 V

0.000000 0.000000 0.000000 Cd

0.500000 0.500000 0.000000 O

0.500000 0.000000 0.500000 O

0.000000 0.500000 0.500000 O

The applied strains are:-0.015 -0.010 -0.005 0.000 0.005 0.010 0.015 for strain stress method with vaspkit assistant. mp-86279 is misspelled, it is mp-862797. Besides, the tensor matric of mp-2967 has a large difference from my calculations.

Thanks for doing the comparison!

There are a few INCAR params different from what we are using, noticeably EDIFF, ENCUT, and LREAL (see The EDIFF in Elastic calculation - #2 by mjwen). Given that, we probably need to look into the calculation details of mp-1016904 to see whether it is converged (and other potential problems) to figure out why there is a large discrepancy. I will check our calculations. Weâ€™ve found that LREAL=AUTO leads to convergence problems for small systems. If possible, it would be great you can recalculate it with LREAL=False and then weâ€™ll see what happens.

We do not have new calculations for mp-2967 yet; will let you know once we got it.