Possible transition between charge density wave and Weyl semimetal phase in Y2Ir2O7

Physical review. B./Physical review. B, vol. 106

Abstract

The subtle interplay of band topology and symmetry broken phase, induced by electron correlations, has immense contemporary relevance and potentially offers novel physical insights. Here, we provide evidence of possible charge density wave (CDW) in bulk ${\mathrm{Y}}_{2}{\mathrm{Ir}}_{2}{\mathrm{O}}_{7}$ for $T<10$ K, and the Weyl semimetal (WSM) phase at higher temperatures. We observe the following characteristic properties of the CDW phase: (i) current induced nonlinear conductivity with negative differential resistance at low temperature, (ii) low-frequency Debye-like dielectric relaxation at low temperature with a large dielectric constant $\ensuremath{\sim}{10}^{8}$, and (iii) an anomaly in the temperature dependence of the thermal expansion coefficient. The WSM phase at higher temperature is analyzed using the dc and ac transport measurements, which show an inductive response at low frequencies. More interestingly, we show that by reducing the crystallite size, the low-temperature CDW phase can be eliminated leading to the restoration of the WSM phase.

Authors 5

1. Abhishek Juyal corresponding

   Georgia Tech-Europe · Centre National de la Recherche Scientifique · Georgia Institute of Technology · Georgia Tech-CNRS Laboratory · Indian Institute of Technology Kanpur

   Affiliation as printed

   Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India

   Georgia Tech Lorraine, IRL 2958-CNRS, 57070 Metz, France

   School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA

2. Vinod Kumar Dwivedi corresponding

   Indian Institute of Science Bangalore · Indian Institute of Technology Kanpur

   Affiliation as printed

   Department of Physics, Indian Institute of Science, Bengaluru 560012, India

   Materials Science Program, Indian Institute of Technology Kanpur, Kanpur 208016, India

3. Sonu Verma

   Institute for Basic Science · Indian Institute of Technology Kanpur

   Affiliation as printed

   Center of Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon 34126, Republic of Korea

   Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India

4. S. Nandi Aachen Lehrstuhl für Experimentalphysik IVc

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University · Indian Institute of Technology Kanpur

   Affiliation as printed

   Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India

   Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-2) and Peter Grünberg Institut (PGI-4), JARA-FIT, 52425 Jülich, Germany

   RWTH Aachen, Lehrstuhl für Experimentalphysik IVc, Jülich-Aachen Research Alliance (JARA-FIT), 52074 Aachen, Germany

5. Soumik Mukhopadhyay

   Indian Institute of Technology Kanpur

   Affiliation as printed

   Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India