Manipulating Dirac States in BaNiS<sub>2</sub> by Surface Charge Doping.

Zhang, Jiuxiang; Sohier, Thibault Daniel Pierre; Casula, Michele; Chen, Zhesheng; Caillaux, Jonathan; Papalazarou, Evangelos; Perfetti, Luca; Petaccia, Luca et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

In the Dirac semimetal BaNiS<sub>2</sub>, 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<sub>2</sub> single crystals. By means of first-principles calculations, we give a full account of 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.