diff --git a/docs/source/tutorial/graphene_example.md b/docs/source/tutorial/graphene_example.md
index 4b2e9826d2aeae9cda18f71c0cd7930866d8e675..afda9f26739a0bd8d842f23032c871d9893b37de 100644
--- a/docs/source/tutorial/graphene_example.md
+++ b/docs/source/tutorial/graphene_example.md
@@ -72,10 +72,10 @@ All we need to do is to convert this object to a tight-binding dictionary using
 
 ```{code-cell} ipython3
 def onsite_int(site, U):
-    return U * np.ones((2, 2))
+    return U * sx
 
 def nn_int(site1, site2, V):
-    return V * np.ones((2, 2))
+    return V * sx
 
 builder_int = utils.build_interacting_syst(
     builder=bulk_graphene,