Two Linear Regimes in Optical Conductivity of a Type-I Weyl Semimetal: The Case of Elemental Tellurium

Diego Rodriguez, Alexander A. Tsirlin, Tobias Biesner, Teppei Ueno, Takeshi Takahashi, Kaya Kobayashi, Martin Dressel, Ece Uykur

    Research output: Contribution to journalArticlepeer-review

    6 Citations (Scopus)

    Abstract

    Employing high-pressure infrared spectroscopy we unveil the Weyl semimetal phase of elemental Te and its topological properties. The linear frequency dependence of the optical conductivity provides clear evidence for metallization of trigonal tellurium (Te-I) and the linear band dispersion above 3.0 GPa. This semimetallic Weyl phase can be tuned by increasing pressure further: a kink separates two linear regimes in the optical conductivity (at 3.7 GPa), a signature proposed for Type-II Weyl semimetals with tilted cones; this however reveals a different origin in trigonal tellurium. Our density-functional calculations do not reveal any significant tilting and suggest that Te-I remains in the Type-I Weyl phase, but with two valence bands in the vicinity of the Fermi level. Their interplay gives rise to the peculiar optical conductivity behavior with more than one linear regime. Pressure above 4.3 GPa stabilizes the more complex Te-II and Te-III polymorphs, which are robust metals.

    Original languageEnglish
    Article number136402
    JournalPhysical Review Letters
    Volume124
    Issue number13
    DOIs
    Publication statusPublished - Apr 3 2020

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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