Study of the electronic ordering in quantum materials of (Rb,K)V₃Sb₅ and Ir₂In₈Se

Yu-Hui Liang^1*, Po-Chun Chang^1,2, Sabreen Hammouda², Shih-Chang Weng³, Yixi Su², Chin-Shan Lue⁴, Wei-Tin Chen⁵, Chao-Hung Du¹

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

* Presenter:Yu-Hui Liang, email:yhl050893@gms.tku.edu.tw

Quantum materials have garnered considerable attention within the realm of condensed matter physics due to their remarkable and captivating physical attributes, which encompass topological insulators and superconductors, as well as intricate spin and charge frustrations, not to mention the presence of Dirac and Weyl semimetals. It has been empirically established that the disparate strengths of electronic ordering, entwined with spins, orbital properties, and lattice interactions, are accountable for the emergence of these extraordinary physical phenomena. Employing X-ray scattering on a kagome metal, (Rb,V)V₃Sb₅, we have discerned an electronic ordering phenomenon, specifically a charge-density wave (CDW) state, which undergoes a subtle second-order transition, exhibiting a profoundly perplexing state within the critical scattering domain. The intermetallic compound Ir₂In₈Se (IIS) undergoes an anomalous transition at around T* ~ 203 K, which has been attributed to the formation of a CDW. Using x-ray scattering, we observed two distinct modulated structures with q_CDW ~ (0.23 0.23 0) and q_Phonon = (0.5 0.5 0), respectively. Both modulations show the different phase transition behavior. We hereby illustrate that the coupling of these order parameters in the transitional domain culminates in an inverse order-disorder transition for the commensurate phase.

Keywords: X-ray Scattering, CDW, Phase Transition