Optical signatures of phase transitions and structural modulation in elemental tellurium under pressure

Phys. Rev. B 101, 174104 (2020) A room-temperature infrared spectroscopy study of elemental tellurium at pressures up to 8.44 GPa in the energy range 0.015-2 eV is reported. Optical signatures of the high-pressure polymorphs are investigated and compared to the results of density-functional band-str...

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Bibliographic Details
Main Authors: Rodriguez, Diego, Tsirlin, Alexander A, Biesner, Tobias, Ueno, Teppei, Takahashi, Takeshi, Kobayashi, Kaya, Dressel, Martin, Uykur, Ece
Format: Journal Article
Language:English
Published: 24-03-2020
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Summary:Phys. Rev. B 101, 174104 (2020) A room-temperature infrared spectroscopy study of elemental tellurium at pressures up to 8.44 GPa in the energy range 0.015-2 eV is reported. Optical signatures of the high-pressure polymorphs are investigated and compared to the results of density-functional band-structure calculations. A Drude peak is first seen in the optical conductivity around 3.5 GPa indicating a semiconductor-to-metal transition within trigonal Te-I. A sharp increase in the Drude spectral weight and dc-conductivity around 4.3 GPa signals the transformation toward the triclinic Te-II polymorph. An absorption peak around 0.15 eV appears above 5 GPa concomitant with the gradual transformation of Te-II into the structurally similar but incommensurately modulated Te-III. Microscopically, this peak can only be reproduced within a sufficiently large commensurate approximant, suggesting the low-energy optical response as a fingerprint of the structural modulation.
DOI:10.48550/arxiv.2003.10741