Study of the electronic ordering in quantum materials of RbV3Sb5 and Ir2In8Se

Yu-Hui Liang¹, Po-Chun Chang¹, Wei-Tin Chen², Yixi Su³, Chin-Shan Lue⁴, Shih-Chang Wen⁵, Chao-Hung Du^1*

¹Department of Physics, Tamkang University, New Taipei City, Taiwan
²The Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
³Quantum Material Group, Jülich Centre for Neutron Science, Jülich, Germany
⁴Department of Physics, National Cheng Kung University, Tainan, Taiwan
⁵X-ray Scattering Group, National Synchrotron Radiation Research Centre, Hsinchu, Taiwan

* Presenter:Chao-Hung Du, email:chd@gms.tku.edu.tw

Quantum materials have attracted lots of attention in condensed matter physics because of their exotic and fascinating physical properties, such as topological insulators/superconductors, geometrical spin/charge frustrations, or Dirac and Weyl semimetals. It has been demonstrated that the different coupling strengths of electronic ordering with spins, orbital, and lattice are responsible for the occurrence of such exotic physical properties. Using x-ray scattering on a Kagome metal RbV3Sb5, we observed an electronic ordering (i.e., a charge-density wave (CDW) state) which shows a weak second order transition with a highly frustrated state in the critical scattering region. The intermetallic compound Ir2In8Se is known as a good candidate of Dirac semimetal. Using x-ray scattering, we observed an incommensurate CDW phase with a q_CDW=(0.5±δ 0.5±δ 0) at TCDW~ 198 K, while a commensurate sublattice appears with a q-vector, q= (0.5 0.5 0). Both modulated sublattices show different transition behavior, i.e., representing different order parameters. We demonstrate that the coupling of both order parameters in the transition region results in an inverse order-disorder transition for the commensurate phase.

Keywords: charge density wave, X-ray scatterig, phase transition, quantum material