Triply degenerate nodal points and topological phase transitions in NaCu3Te2

Article

关键词: HGTE QUANTUM-WELLS;    SINGLE DIRAC CONE;    MAJORANA FERMIONS;    WANNIER FUNCTIONS;    SURFACE;    INSULATOR;    SEMIMETAL;    SUPERCONDUCTOR;    SCHEMES;    BI2TE3;   

DOI  :  10.1103/PhysRevB.96.241204

来源: SCIE

【 摘 要 】

Quasiparticle excitations of free electrons in condensed-matter physics, characterized by the dimensionality of the band crossing, can find their elementary-particle analogs in high-energy physics, such as Majorana, Weyl, and Dirac fermions, while crystalline symmetry allows more quasiparticle excitations and exotic fermions to emerge. Using symmetry analysis and ab initio calculations, we propose that the three-dimensional honeycomb crystal NaCu3Te2 hosts triply degenerate nodal points (TDNPs) residing at the Fermi level. Furthermore, in this system we find a tunable phase transition between a trivial insulator, a TDNP phase, and a weak topological insulator (TI), triggered by a symmetry-allowed perturbation and the spin-orbital coupling (SOC). Such a topological nontrivial ternary compound not only serves as a perfect candidate for studying three-component fermions, but also provides an excellent playground for understanding the topological phase transitions between TDNPs, TIs, and trivial insulators, which distinguishes this system from other TDNP candidates.

【 授权许可】

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