• Featured in Physics
  • Editors' Suggestion

Symmetry breaking and unconventional charge ordering in single crystal Na2.7Ru4O9

Arvind Yogi, C. I. Sathish, Hasung Sim, Matthew J. Coak, Y. Noda, and Je-Geun Park
Phys. Rev. B 98, 085113 – Published 7 August 2018
Physics logo See Synopsis: Unusual Properties of a Ruthenium-Based Crystal  
PDFHTMLExport Citation

Abstract

The interplay of charge, spin, and lattice degrees of freedom in matter leads to various forms of ordered states through phase transitions. An important subclass of these phenomena of complex materials is charge ordering (CO), mainly driven by mixed-valence states. We discovered by combining the results of electrical resistivity (ρ), specific heat, susceptibility (χ), and single crystal x-ray diffraction (SC-XRD) that Na2.7Ru4O9 with the monoclinic tunnel type lattice (space group C2/m) exhibits an unconventional CO at room temperature while retaining metallicity. The temperature-dependent SC-XRD results show successive phase transitions with superlattice reflections at q1=(0,12,0) and q2=(0,13,13) below TC2 (365 K) and only at q1=(0,12,0) between TC2 and TC1 (630 K). We interpreted these as evidence for the formation of an unconventional CO. It reveals a strong first-order phase transition in the electrical resistivity at TC2 (cooling) = 345 K and TC2 (heating) = 365 K. We argue that the origin of the phase transition is due to the localized 4d Ru electrons. The results of our finding reveal an unique example of Ru3+/Ru4+ mixed valance heavy d4 ions.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
3 More
  • Received 30 March 2018

DOI:https://doi.org/10.1103/PhysRevB.98.085113

©2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Synopsis

Key Image

Unusual Properties of a Ruthenium-Based Crystal  

Published 7 August 2018

Experiments on a ruthenium-based material uncover an electron-ordering pattern that leads to surprising macroscopic behavior.  

See more in Physics

Authors & Affiliations

Arvind Yogi1,2,*, C. I. Sathish1,2, Hasung Sim1,2, Matthew J. Coak1,2, Y. Noda3,4, and Je-Geun Park1,2,†

  • 1Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea
  • 2Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
  • 3J-PARC center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
  • 4Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan

  • *yogi.arvind2003@gmail.com
  • jgpark10@snu.ac.kr

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 98, Iss. 8 — 15 August 2018

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×