TY - JOUR
T1 - Two Linear Regimes in Optical Conductivity of a Type-I Weyl Semimetal
T2 - The Case of Elemental Tellurium
AU - Rodriguez, Diego
AU - Tsirlin, Alexander A.
AU - Biesner, Tobias
AU - Ueno, Teppei
AU - Takahashi, Takeshi
AU - Kobayashi, Kaya
AU - Dressel, Martin
AU - Uykur, Ece
N1 - Funding Information:
We acknowledge fruitful discussions with Artem V. Pronin and Sascha Polatkan; technical support from Gabriele Untereiner. We are grateful to Malcolm McMahon for sharing his x-ray data for our calculations. Work in Okayama is supported by the Grant-in-Aid for Scientific Research (Grants No. 18K03540, No. 19H01852). E. U. acknowledges the European Social Fund and the Baden-Württemberg Stiftung for the financial support of this research project by the Eliteprogramme.
Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/4/3
Y1 - 2020/4/3
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevLett.124.136402
DO - 10.1103/PhysRevLett.124.136402
M3 - Article
C2 - 32302162
AN - SCOPUS:85083755227
SN - 0031-9007
VL - 124
JO - Physical Review Letters
JF - Physical Review Letters
IS - 13
M1 - 136402
ER -