## Surface get started and input examples

`Surface` calculates the surface energy. We need to give the information of `min_slab_size`, `min_vacuum_size`, `max_miller` (default value is 2), and `pert_xz` which means perturbations in xz and will help work around vasp bug.

#### An example of the input file for Surface by deepmd:

```json
{
  "structures": "confs/mp-*",
  "interaction": {
    "type": "deepmd",
    "model": "frozen_model.pb",
    "type_map": {
      "Al": 0,
      "Mg": 1
    }
  },
  "properties": [
    {
      "type": "surface",
      "min_slab_size": 10,
      "min_vacuum_size": 11,
      "max_miller": 2,
      "cal_type": "static"
    }
  ]
}
```