Résumé
In the Dirac semimetal BaNiS$_2$ , the Dirac nodes are located along the Γ − M symmetry line of the Brillouin zone, instead of being pinned at fixed high-symmetry points. We take advantage of this peculiar feature to demonstrate the possibility of moving the Dirac bands along the Γ − M symmetry line in reciprocal space by varying the concentration of K atoms adsorbed onto the surface of cleaved BaNiS$_2$ single crystals. By means of first-principles calculations, we give full account for this observation by considering the effect of the electrons donated by the K atom on the charge transfer gap, which establishes a promising tool for engineering Dirac states at surfaces, interfaces and heterostructures.