Within the scope of the locally rotationally symmetric (LRS) Bianchi type-I cosmological model the role of spinor field on the evolution of the Universe is investigated. In doing so, we have considered a polynomial type of nonlinearity. It is found that, depending on the sign of the self-coupling constant, the model allows either an accelerated mode of expansion or an oscillatory mode of evolution. While the non-diagonal components of the energy–momentum tensor of the spinor field in the case of a full Bianchi type-I model lead to the vanishing mass and nonlinear term in the spinor field Lagrangian, in the case of an LRS Bianchi type-I model neither the mass term nor the nonlinear term of the spinor field vanish.
Nonlinear spinor field in Bianchi type-I Universe filled with perfect fluid: Exact self-consistent solutions