Diamond lattice in single-component molecular crystals comprising tetrabenzoporphyrin neutral radicals

Abstract

A single-component molecular radical crystal of Co^III(tbp˙⁻)(CN)₂, where tbp = tetrabenzoporphyrinato ligand, exhibiting a diamond lattice was fabricated as a potential candidate for a three-dimensional Dirac electron system. Band structure calculations revealed that the Fermi energy level was located at the Dirac point. A small electrical resistivity of 160 Ω cm was observed at 2 K under the application of 2.4 GPa. Furthermore, substituting Co^III by Fe^III or Mn^III led to the introduction of local magnetic moments into the diamond-lattice system. M^III(tbp˙⁻)L₂ crystals will open up uncharted fields in the study of the Dirac electron systems.