/*******************************************************************************/
/
/ These are the examples of ABACUS program.
/
/*******************************************************************************/

ABACUS supports adding a saw-like potential simulating an electric field
can to the bare ionic potential, which is a simplified simulation to the field-effect measurements, in which the system is separated from the gate electrode by a dielectric such as silicon oxide.

An external electric field can be added with the following 
parameters in INPUT file, 

```
INPUT_PARAMETERS
efield_flag        1
efield_dir         2
efield_pos_max     0.5
efield_pos_dec     0.1
efield_amp         0.001
```

Detailed explaination of these keywords can be found [here](https://github.com/deepmodeling/abacus-develop/blob/develop/docs/input-main.md#electric-field-and-dipole-correction). The energy contribution from the added external field is given as `E_efield` in the output file. See `running_scf.ref` for the output of this example. Note that both `pw` and `lcao` (specified via `basis type`) are supported for this functionality. 


