Electronic and phonon excitations in αRuCl3

S. Reschke, F. Mayr, Zhe Wang, Seung-Hwan Do, K.-Y. Choi, and A. Loidl
Phys. Rev. B 96, 165120 – Published 11 October 2017

Abstract

We report on terahertz (THz), infrared reflectivity, and transmission experiments for wavenumbers from 10 to 8000cm1 (1meV1eV) and for temperatures from 5 to 295 K on the Kitaev candidate material αRuCl3. As reported earlier, the compound under investigation passes through a first-order structural phase transition, from a monoclinic high-temperature to a rhombohedral low-temperature phase. The phase transition shows an extreme and unusual hysteretic behavior, which extends from 60 to 166 K. In passing this phase transition, in the complete frequency range investigated, we found a significant reflectance change, which amounts to almost a factor of two. We provide a broadband spectrum of dielectric constant, dielectric loss, and optical conductivity from the THz to the mid-infrared regime and study in detail the phonon response and the low-lying electronic density of states. We provide evidence for the onset of an optical energy gap, which is on the order of 200 meV, in good agreement with the gap derived from measurements of the dc electrical resistivity. Remarkably, the onset of the gap exhibits a strong blue shift on increasing temperatures.

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  • Received 8 June 2017
  • Revised 4 August 2017

DOI:https://doi.org/10.1103/PhysRevB.96.165120

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

S. Reschke1, F. Mayr1, Zhe Wang1,2, Seung-Hwan Do3, K.-Y. Choi3, and A. Loidl1,*

  • 1Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany
  • 2Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
  • 3Department of Physics, Chung-Ang University, Seoul 06974, Republic of Korea

  • *alois.loidl@physik.uni-augsburg.de

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Issue

Vol. 96, Iss. 16 — 15 October 2017

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