[15p-P05-1~62] 17 Nanocarbon and Two-Dimensional Materials (Poster)

[15p-P05-50] Polarized Raman spectroscopy analysis of the excitonic insulator Ta₂NiSe₅

〇Masako Suzuki¹, Sarah Harmer², Sara Miller², Yoshiaki Kobayashi³, Yukinori Ohta⁴ (1.Gunma Univ., 2.Flinders Univ., 3.Nagoya Univ., 4.Chiba Univ.)

Keywords:

Transition metal chalcogenide,Raman Spectroscopy

In transition-metal chalcogenide materials such as Ta₂NiSe₅, a phase transition to a low-temperature phase caused possibly by the condensation of spin-singlet electron-hole pairs (or excitons) has been reported to occur. A recent report has also suggested that a crossover temperature exist far above the transition temperature, where the preformed pair state appears, leading to an intense discussion on the precursor phenomena of the excitonic phase transition. In this study, we perform polarized Raman analysis of Ta₂NiSe₅ and observe the local structural changes that occur around the crossover temperature.