Non-trivial band topology in Bi doped Lanthanum monopnictides (LaX; X = As and Sb)

Abstract

In this study, we report first-principles investigation of non-trivial topological characteristics in Bi doped Lanthanum monopnictides, particularly LaAs and LaSb. For this, we varied the concentration of Bi atoms in 1 × 1 × 2 supercell of LaAs and LaSb unit cells along [001] direction, and phonon-dispersion spectra of all these doped arrangements are observed to be dynamically stable.HSE06 band structure calculations with spin–orbit coupling reveal that the non-trivial topological characteristics starts appearing in 50% concentration of Bi atoms in the given supercells of LaAs and LaSb. The non-trivial topological characteristics in the proposed doped arrangements are verified by bulk band inversion, unit Z2 topological invariant, and a surface Dirac cone. Our findings provide promising candidates of non-trivial topological family, which may carry huge potential for extremely large magnetoresistance and spintronics applications.