Electronic and magnetic properties of antiferromagnetic TbAs via modified Becke Johnson potential plus an on-site Coulomb U

Abstract

In this work, theoretical study of structural, elastic, electronic properties and magnetic ordering of Terbium arsenide (TbAs) in NaCl-B1 and CsCl-B2 phases are investigated using first-principles calculations based on the full-potential augmented plane wave plus local orbitals (FP-L/APW ‏+ lo) method within the framework of density functional theory (DFT) in the generalized gradient approximation (GGA) with the on-site Hubbard Ueff parameter (GGA+U). At ambient conditions Terbium monopnictides stabilize in NaCl (B1) structure. The calculations indicate that there exists a phase transition from the NaCl-type (B1) structure to CsCl-type (B2) structure at the transition pressure of 16GPa. The calculated structural parameters, such as the lattice constant, bulk modulus and second-order elastic constants, are presented. Elastic constants and their related parameters such as Poisson's ratio, Young modulus and shear modulus were calculated. The anti-ferromagnetic of type II state is found to be the most stable than the other possible phases, which is in agreement with experiment. By varying the Hubbard U parameter from 0 to 10eV, a detailed study of magnetism of this compound via the density of states DOS, is presented. We find that semiconducting band structures can be obtained using the modified Becke-Johnson potential plus an on-site Coulomb U (the mBJ+U approach).