  Semi-Dirac semimetal is a material exhibiting linear band dispersion in one
direction and quadratic band dispersion in the orthogonal direction and,
therefore, hosts massless and massive fermions at the same point in the
momentum space. While a number of interesting physical properties have been
predicted in semi-Dirac semimetals, it has been rare to realize such materials
in condensed matters. Based on the fact that some honeycomb materials are
easily oxidized or chemically absorb other atoms, here, we theoretically
propose an approach of modifying their band structures by covalent addition of
group-VI elements and strain engineering. We predict a silicene oxide with
chemical formula of Si2O to be a candidate of semi-Dirac semimetal. Our
approach is backed by the analysis and understanding of the effect of p-orbital
frustration on the band structure of the graphene-like materials.
