Unstable Stacking Fault Energy (USFE)¶

USFEAnalyzer ¶

USFEAnalyzer(
    slip_plane: str = "110",
    start: float = 0.0,
    stop: float = 1.0,
    num_steps: int = 11,
    calculator: BaseCalculator | None = None,
    usfe_transformation: USFETransformation | None = None,
)

A class used to compute GSFE curves and USFE values for BCC-like slip systems.

Initializes the USFEAnalyzer object.

Parameters:

Name	Type	Description	Default
`slip_plane`	`str`	Slip plane label, either `"110"` or `"112"`. Defaults to `"110"`.	`'110'`
`start`	`float`	Starting displacement fraction. Defaults to 0.0.	`0.0`
`stop`	`float`	Ending displacement fraction. Defaults to 1.0.	`1.0`
`num_steps`	`int`	Number of displacement points. Defaults to 11.	`11`
`calculator`	`BaseCalculator \| None`	Calculator for energy evaluations.	`None`
`usfe_transformation`	`USFETransformation \| None`	Custom transformation object. If not provided, a default one is created lazily.	`None`

Raises:

Type	Description
`ValueError`	If `slip_plane` is not supported.

calculate ¶

calculate(
    structure: Structure | Atoms, is_relaxed: bool = False
) -> dict[str, str | int | float | list[dict[str, float]]]

Calculates GSFE curve and USFE for a given structure.

Parameters:

Name	Type	Description	Default
`structure`	`Structure \| Atoms`	Input structure.	required
`is_relaxed`	`bool`	Whether input is already relaxed. Defaults to False.	`False`

Returns:

Type	Description
`dict[str, str \| int \| float \| list[dict[str, float]]]`	dict[str, str \| int \| float \| list[dict[str, float]]]: Dictionary with keys: - `gsfe_curve`: GSFE samples for each displacement step. - `usfe_mJ_m2`: Maximum GSFE value (unstable stacking fault energy) in mJ/m^2. - `usfe_displacement_frac`: Displacement fraction at the USFE peak. - `slip_plane`: Slip plane used for displacement. - `num_steps`: Number of displacement steps used in the scan.

Raises:

Type	Description
`ValueError`	If the calculator does not provide `energy`.

usfe_transformation ¶

usfe_transformation() -> USFETransformation

Return USFE transformation object for displaced structures.

Returns:

Type	Description
`USFETransformation`	USFE transformation instance.