Observation of surface Dirac dispersion in transition metal dipnictides*

The experimental discovery of Dirac and Weyl Fermions, quasi-particles existing in low energy excitation in condensed matter physics, has paved a new avenue of research interests in condensed matter physics. Recently, the Lorentz-invariance breaking Weyl semimetallic state has been reported in MoP₂ and WP₂. Arsenic counterparts of these compounds, which also harbor high magnetoresistance, demand the detailed study to investigate the possible semimetallic state possessed by them. Here, we discuss our angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations results on the electronic structures of MoAs₂ and WAs₂, which reveal the presence of a surface Dirac cone. Our systematic electronic structures analysis reveals the termination dependent electronic structure in these compounds. Our study offers the opportunity to study the various quantum phase transitions within this family.