diff --git a/src/nomad_simulations/properties/band_structure.py b/src/nomad_simulations/properties/band_structure.py
index d911f8a0..4e35ab49 100644
--- a/src/nomad_simulations/properties/band_structure.py
+++ b/src/nomad_simulations/properties/band_structure.py
@@ -59,7 +59,7 @@ def __init__(
     ) -> None:
         super().__init__(m_def, m_context, **kwargs)
         # ! `n_bands` need to be set up during initialization of the class
-        self.rank = [kwargs.get('n_bands')]
+        self.rank = [int(kwargs.get('n_bands'))]
 
     def normalize(self, archive, logger) -> None:
         super().normalize(archive, logger)
diff --git a/src/nomad_simulations/properties/fermi_surface.py b/src/nomad_simulations/properties/fermi_surface.py
index b8ce7972..5d8392b2 100644
--- a/src/nomad_simulations/properties/fermi_surface.py
+++ b/src/nomad_simulations/properties/fermi_surface.py
@@ -45,7 +45,7 @@ def __init__(
     ) -> None:
         super().__init__(m_def, m_context, **kwargs)
         # ! `n_bands` need to be set up during initialization of the class
-        self.rank = [kwargs.get('n_bands')]
+        self.rank = [int(kwargs.get('n_bands'))]
         self.name = self.m_def.name
 
     def normalize(self, archive, logger) -> None:
diff --git a/src/nomad_simulations/properties/hopping_matrix.py b/src/nomad_simulations/properties/hopping_matrix.py
index 2ea16313..7eb6713d 100644
--- a/src/nomad_simulations/properties/hopping_matrix.py
+++ b/src/nomad_simulations/properties/hopping_matrix.py
@@ -60,7 +60,7 @@ def __init__(
     ) -> None:
         super().__init__(m_def, m_context, **kwargs)
         # ! n_orbitals need to be set up during initialization of the class
-        self.rank = [kwargs.get('n_orbitals'), kwargs.get('n_orbitals')]
+        self.rank = [int(kwargs.get('n_orbitals')), int(kwargs.get('n_orbitals'))]
         self.name = self.m_def.name
 
     # TODO add normalization to extract DOS, band structure, etc, properties from `HoppingMatrix`
@@ -97,7 +97,7 @@ def __init__(
     ) -> None:
         super().__init__(m_def, m_context, **kwargs)
         # ! `n_orbitals` need to be set up during initialization of the class
-        self.rank = [kwargs.get('n_orbitals')]
+        self.rank = [int(kwargs.get('n_orbitals'))]
         self.name = self.m_def.name
 
     def normalize(self, archive, logger) -> None: