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src/nomad_simulations/schema_packages/properties/band_gap.py

@@ -6,8 +6,6 @@
 from nomad.metainfo import MEnum, Quantity
 from nomad.metainfo.physical_properties import MaterialProperty, Energy
 from ..variables import (
-    MaterialPropertyAttributes,
-    fetch_instance,
     SpinChannel,
     MomentumTransfer,
 )
@@ -21,7 +19,7 @@ class ElectronicBandGap(ArchiveSection):  # ! TODO: add optical band gap
     values = MaterialProperty(
         name='BandGap',
         fields=[Energy],
-        variables=[SpinChannel, MomentumTransfer],  # target index
+        variables=[SpinChannel, MomentumTransfer],  # presence checked via annotations
         iri='http://fairmat-nfdi.eu/taxonomy/ElectronicBandGap',
         description="""Energy difference between the highest occupied electronic state and the lowest unoccupied electronic state.""",  # ? necessity
     )
@@ -41,20 +39,7 @@ def normalize(self, archive: 'EntryArchive', logger: 'BoundLogger') -> None:
         if np.any(self.values.fields < 0):  # ? check for Energy
             logger.warning(f'Negative band gap detected: {self.values.fields} J')
 
-        if np.any(
-            fetch_instance(
-                self, SpinChannel, attribute=MaterialPropertyAttributes.variables
-            )
-        ):
-            logger.warning(
-                f'Band gap without specifying any spin channel: {self.values.variables}'
-            )
-
-        if not np.any(
-            fetch_instance(
-                self, MomentumTransfer, attribute=MaterialPropertyAttributes.variables
-            )
-        ):
+        if not self.variables[1]:  # ! replace with native getter
             if self.type == 'direct':
                 self.variables.append(
                     MomentumTransfer(data=[2 * [3 * [0.0]]] * ureg.angstrom**-1)
@@ -63,5 +48,3 @@ def normalize(self, archive: 'EntryArchive', logger: 'BoundLogger') -> None:
                 logger.warning(
                     f'Indirect band gap without specifying any momentum transfer: {self.variables}'
                 )
-
-        # ? how to enforce a fixed ordering

src/nomad_simulations/schema_packages/properties/band_structure.py

@@ -88,7 +88,7 @@ class ElectronicEigenstates(ArchiveSection):
     )  # ? remove
 
     highest_occupied = Quantity(
-        type=np.float64,
+        type=np.float64,  # ! energy, k-point
         unit='joule',
         description="""
         Highest occupied electronic eigenvalue. Together with `lowest_unoccupied`, it defines the
@@ -97,7 +97,7 @@ class ElectronicEigenstates(ArchiveSection):
     )
 
     lowest_unoccupied = Quantity(
-        type=np.float64,
+        type=np.float64,  # ! energy, k-point
         unit='joule',
         description="""
         Lowest unoccupied electronic eigenvalue. Together with `highest_occupied`, it defines the

src/nomad_simulations/schema_packages/variables.py

@@ -22,37 +22,6 @@
 )
 
 
-class MaterialPropertyAttributes(Enum):
-    fields = 'fields'
-    variables = 'variables'
-
-
-def fetch_instance(
-    prop: MaterialProperty,
-    target: PhysicalProperty,
-    attribute: MaterialPropertyAttributes = MaterialPropertyAttributes.fields,
-) -> np.ndarray[PhysicalProperty]:
-    """
-    Fetches instances of a specified physical property from a material property based on a given attribute.
-
-    Args:
-        prop (MaterialProperty): The material property from which to fetch instances.
-        target (PhysicalProperty): The type of physical property to fetch.
-        attribute (MaterialPropertyAttributes): The attribute of the material property to check.
-
-    Returns:
-        np.ndarray[PhysicalProperty]: An array of instances of the specified physical property.
-
-    Raises:
-        ValueError: If the provided attribute is not a valid MaterialProperty attribute.
-    """
-    if not isinstance(attribute, MaterialPropertyAttributes):
-        raise ValueError(
-            f'Attribute {attribute} is not a valid MaterialProperty attribute.'
-        )
-    return np.where(lambda x: isinstance(x, target), getattr(prop, attribute), [])
-
-
 SpinChannel = PhysicalProperty(
     name='SpinChannel',
     type=MEnum('alpha', 'beta', 'both'),