Strong topological metal material with multiple Dirac cones

Article

关键词: SEMIMETAL;    INSULATOR;    MOBILITY;   

DOI  :  10.1103/PhysRevB.93.045315

来源: SCIE

【 摘 要 】

We report a new, cleavable, strong topological metal, Zr2Te2P, which has the same tetradymite-type crystal structure as the topological insulator Bi2Te2Se. Instead of being a semiconductor, however, Zr2Te2P is metallic with a pseudogap between 0.2 and 0.7 eV above the Fermi energy (E-F). Inside this pseudogap, two Dirac dispersions are predicted: one is a surface-originated Dirac cone protected by time-reversal symmetry (TRS), while the other is a bulk-originated and slightly gapped Dirac cone with a largely linear dispersion over a 2 eV energy range. A third surface TRS-protected Dirac cone is predicted, and observed using angle-resolved photoemission spectroscopy, making Zr2Te2P the first system, to our knowledge, to realize TRS-protected Dirac cones at (M) over bar points. The high anisotropy of this Dirac cone is similar to the one in the hypothetical Dirac semimetal BiO2. We propose that if E-F can be tuned into the pseudogap where the Dirac dispersions exist, it may be possible to observe ultrahigh carrier mobility and large magnetoresistance in this material.

【 授权许可】

Free