Young's modulus of mp-696497

Hello everyone, I got a question about the Young’s modulus for mp-696497. From the structure of the crystal, it is obvious that c direction will have the smallest Young’s modulus, and a and b directions have similar Young’s modulus. However, when I look at the stiffness matrix, I saw aa direction has much smaller value and bb and cc direction has similar high value. If I understand correctly, this value isn’t Young’s modulus but should be correlated with Young’s modulus along different directions.

My question is, is there a problem with the matrix or I am reading the data incorrectly? Thanks,

Hi cchen83,

Sorry for the delay on this, I’m looking into this now and will update when I have an explanation.

Hi Cchen83, thanks very much for bringing this to our attention, it looks like there’s a bug in the IEEE conversion procedure for triclinic structures, which should be fixed on the next release of pymatgen. We’ll be rebuilding the database in the next week or so to fix the issue.

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Just FYI, PR to pymatgen is here.