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arXiv · 2507.06550

Material realization of spinless, covalent-type Dirac semimetals in three dimensions

Yuki Tanaka·Rinsuke Yamada·Manabu Sato·Motoaki Hirayama·Max Hirschberger
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Abstract

Realization of a three-dimensional (3D) analogue of graphene has been a central challenge in topological materials science. Graphene is stabilized by covalent bonding unlike conventional spin-orbit type 3D Dirac semimetals (DSMs). In this study, we demonstrate the material realization of covalent-type 3D DSMs $R_8$Co$X_3$ stabilized by covalent bonding. We observe that the carrier mobility $\mu$ of Dirac fermions reaches 3,000$\,\mathrm{cm^2/Vs}$ even in polycrystalline samples, and $\mu$ increases with the inverse of the Fermi energy, evidencing significant contributions to charge transport from Dirac electrons. $R_8$Co$X_3$ provides a material platform for exploration of Dirac electrons in three dimensions with wide chemical tunability.

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Yuki Tanaka, Rinsuke Yamada, Manabu Sato, Motoaki Hirayama, Max Hirschberger. 2025-07-09. Material realization of spinless, covalent-type Dirac semimetals in three dimensions. https://doi.org/10.1103/pshy-l48q

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