【公開日：2025.06.10】【最終更新日：2025.04.18】

課題データ / Project Data

課題番号 / Project Issue Number

24QS0106

利用課題名 / Title

Characterization of the excitons in a superatomic semiconductor

利用した実施機関 / Support Institute

量子科学技術研究開発機構 / QST

機関外・機関内の利用 / External or Internal Use

外部利用/External Use

技術領域 / Technology Area

【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-

【重要技術領域 / Important Technology Area】（主 / Main）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions（副 / Sub）-

キーワード / Keywords

Orbital Excitations, Superatom, Exciton, Resonant Inelastic X-ray Scattering,量子効果/ Quantum effect,放射光/ Synchrotron radiation,超伝導/ Superconductivity

利用者と利用形態 / User and Support Type

利用者名（課題申請者）/ User Name (Project Applicant)

Shen Yao

所属名 / Affiliation

Institute of Physics, Chinese Academy of Sciences

共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes

Zhang Guangkai

ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes

石井 賢司

利用形態 / Support Type

（主 / Main）共同研究/Joint Research（副 / Sub）-

利用した主な設備 / Equipment Used in This Project

QS-112：共鳴非弾性X線散乱装置

報告書データ / Report

概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)

Recently, exciton-polarons with quasi-ballistic propagation have been discovered in a superatomic van der Waals material Re₆Se₈Cl₂, promising for lossless nanoelectronics. However, the electronic character and propagation details of the excitons remain unknown. In the current experiment, we use resonant inelastic x-ray scattering at Re L₃ edge to study the electronic structure and excitons by probing the orbital excitations and dispersions.

実験 / Experimental

Resonant inelastic x-ray scattering (RIXS) is a powerful tool to probe various elementary excitations, including charge, orbital, spin and lattice dynamics. The Re₆Se₈Cl₂ single crystal was pre-aligned and mounted to the sample holder using silver paint. We used a cryostat to cool the sample down to 9 K and determine its orientation using two inequivalent Bragg peaks. We collected RIXS energy maps by collecting RIXS spectra with varying incident photon energy. We also performed similar measurements at a high temperature of 300 K to investigate potential thermal fluctuation induced electronic behavior change. All the measurements were conducted at the Re L₃ edge with pi polarization (incident photon polarization parallel to the horizontal scattering plane).

結果と考察 / Results and Discussion

We observed well defined electronic excitations above ~1.5 eV energy loss, consistent with its electronic band gap size determined from optical measurements, indicating negligible electronic correlations for this material. We did not observe any exciton-like feature at ~1.4 eV energy loss but weak in-gap excitations were revealed at around 1 eV energy loss right at the resonant peak energy, the origin of which remains unclear.

図・表・数式 / Figures, Tables and Equations

その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)

成果発表・成果利用 / Publication and Patents

論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)

口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.

特許 / Patents

特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件