Elastic post

The ElasticTensor module in pymatgen.analysis.elasticity.elastic is used to get the elastic tensor, Bv, and Gv. The mechanical properties of a crystal structure would be written in result.json in json format and result.out in txt format. The example of the output file is give below.

result.json

{
    "elastic_tensor": [
        134.90955999999997,
        54.329958699999985,
        51.802386099999985,
        3.5745279599999993,
        -1.3886325999999648e-05,
        -1.9638233999999486e-05,
        54.55840299999999,
        134.59654699999996,
        51.7972336,
        -3.53972684,
        1.839568799999963e-05,
        8.756799399999951e-05,
        51.91324859999999,
        51.913292199999994,
        137.01763799999998,
        -5.090339399999969e-05,
        6.99251629999996e-05,
        3.736478699999946e-05,
        3.8780564440000007,
        -3.770445632,
        -1.2766205999999956,
        35.41343199999999,
        2.2479590800000023e-05,
        1.3837692000000172e-06,
        -4.959999999495933e-06,
        2.5800000003918792e-06,
        1.4800000030874965e-06,
        2.9000000008417968e-06,
        35.375960199999994,
        3.8608356,
        0.0,
        0.0,
        0.0,
        0.0,
        4.02554856,
        38.375018399999995
    ],
    "BV": 80.3153630222222,
    "GV": 38.40582656,
    "EV": 99.37716395728943,
    "uV": 0.2937771799031088
}

The order of elastic_tensor is C11, C12, …, C16, C21, C22, …, C26, …, C66 and the unit of Bv, Gv, Ev, and uv is GPa.

result.out

/root/auto_test_example/deepmd/confs/std-fcc/elastic_00
 134.91   54.33   51.80    3.57   -0.00   -0.00
  54.56  134.60   51.80   -3.54    0.00    0.00
  51.91   51.91  137.02   -0.00    0.00    0.00
   3.88   -3.77   -1.28   35.41    0.00    0.00
  -0.00    0.00    0.00    0.00   35.38    3.86
   0.00    0.00    0.00    0.00    4.03   38.38
# Bulk   Modulus BV = 80.32 GPa
# Shear  Modulus GV = 38.41 GPa
# Youngs Modulus EV = 99.38 GPa
# Poission Ratio uV = 0.29