Comment on “Solutions of Noncommutative Two-Dimensional Position-Dependent Mass Dirac Equation in the Presence of Rashba Spin-Orbit Interaction by Using the Nikiforov-Uvarov Method”

In this comment, we showed that it is a mistake to work with the Dirac equation in the form presented by Haouam. Indeed, this happens because the Rashba Hamiltonian is a direct result of the non-relativistic limit of the Dirac equation and, therefore, it makes no sense to use such a Hamiltonian in the Dirac Hamiltonian itself, as Haouam did. Therefore, Haouam cannot simply introduce a non-relativistic Hamiltonian into the relativistic Hamiltonian itself in which it originated (this is something physically inconsistent). However, one way to get around this error would be if Haouam had applied his problem to “massive” graphene, where the Dirac equation with the Rashba coupling makes more sense (but it was not the case).