Topological surface states in Ta₃Sb

Topological superconductors are fascinating platforms for realizing Majorana zero modes, which are crucial for the advancement of topological quantum computing. Ta₃Sb is one of the A15 superconductors that possesses topologically nontrivial electronic structures, along with associated topological surface states. Here, we theoretically investigate the topological surface states of Ta₃Sb using first-principles calculations based on density functional theory. We examine how the configurations of surface states change depending on surface termination and atomic relaxation. Our findings reveal that different surface terminations and atomic relaxation effects lead to significantly varied topological surface band structures with distinct Dirac point energies, while still preserving the topologically nontrivial characteristics. Additionally, chemical passivation of the surface atoms can be employed to simplify the configurations of the surface states. Our results provide critical insights into the tunability and stability of surface states in Ta₃Sb, which are essential for future experimental studies and the practical realization of topological quantum computing.