  Entanglement is considered a fundamental ingredient for quantum technologies
and condensed matter systems are among the good candidates for quantum devices.
For bipartite pure states the von Neumann entropy is a proper measure of
entanglement, while the linear entropy, associated to the mixedness of the
reduced density matrices, is a simpler quantity to be obtained and is
considered to be qualitatively equivalent to the von Neumann. Here we
investigate both linear and von Neumann entropies for quantifying entanglement
in homogeneous, superlattice and disordered Hubbard chains. We find regimes of
parameters for which the linear entropy fails in reproducing the qualitative
behavior of the von Neumann entropy. This then may lead to incorrect
predictions i) of maximum and minimum entanglement states and ii) of quantum
phase transitions.
