Unconventional free charge in the correlated semimetal Nd2Ir2O7

Wang, K.; Xu, Bing; Rischau, C. W.; Bachar, N.; Michon, B.; Teyssier, J.; Qiu, Y.; Ohtsuki, T.; Cheng, Bing; Armitage, N. P.; Nakatsuji, S.; van der Marel, D.

doi:10.1038/s41567-020-0955-0

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Journal article

Unconventional free charge in the correlated semimetal Nd2Ir2O7

Wang, K. Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
Xu, Bing Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Fribourg, Switzerland
Rischau, C. W. Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
Bachar, N. Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
Michon, B. Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
Teyssier, J. Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
Qiu, Y. Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
Ohtsuki, T. Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
Cheng, Bing The Institute for Quantum Matter and the Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA
Armitage, N. P. The Institute for Quantum Matter and the Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA
Nakatsuji, S. Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan - The Institute for Quantum Matter and the Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD, USA - CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan - Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
van der Marel, D. Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland

29.06.2020

Published in:

Nature Physics. - 2020, vol. 16, no. 12, p. 1194-1198

English Nd2Ir2O7 is a correlated semimetal with the pyrochlore structure, in which competing spin–orbit coupling and electron–electron interactions are believed to induce a time- reversal symmetry-broken Weyl semimetal phase characterized by pairs of topologically protected Dirac points at the Fermi energy1,2,3,4. However, the emergent properties in these materials are far from clear, and exotic new states of matter have been conjectured5,6,7. Here, we demonstrate optically that, at low temperatures, the free carrier spectral weight is proportional to T2, where T is the temperature, as expected for massless Dirac electrons. However, we do not observe the corresponding T3 term in the specific heat. That the system is not in a Fermi liquid state is further corroborated by the charge carrier scattering rate approaching critical damping and the progressive opening of a correlation-induced gap at low temperatures. These observations cannot be reconciled within the framework of band theory of electron-like quasiparticles and point towards the effective decoupling of the charge transport from the single particle sector.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

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