期刊論文

學年 113
學期 2
出版（發表）日期 2025-04-11
作品名稱 Structural instability and charge transfer mediated transition in Pr3Co4Sn13: Asynchrotron radiation based scattering and spectroscopic study
作品名稱（其他語言）
著者 Surajit Ghosh, Chin-Wei Li, Chih-En Hsu, Chao-Hung Du, Jau-Wern Chiou*, Yu-Hui Liang, Wei-Xuan Lin, Kuan-Hung Chen, Hsio-Tsu Wang, Huang-Ming Tsai, Jeng-Lung Chen, Chih-Wen Pao, Cheng-Maw Cheng, Chia-Nung Kuo, Chin-Shan Lue, Sekhar Chandra Ray, Hung-Chung Hsueh(薛宏中)*, and Way-Faung Pong*
單位
出版者
著錄名稱、卷期、頁數 Physical Review B, vol. 111, p.165119
摘要 This study aims to clarify the physics of the transition that is observed in P⁢r3⁢C⁢o4⁢S⁢n13 (PCS) by specific heat at ∼138 K, which resembles the formation of a charge density wave (CDW). The work is performed using synchrotron radiation based scattering and spectroscopic techniques that include temperature-dependent x-ray diffraction (XRD), x-ray scattering (XRS), x-ray absorption near-edge structure (XANES)/extended x-ray absorption fine structure (EXAFS), resonant inelastic x-ray spectroscopy (RIXS), valence-band photoemission (VB-PES), and first-principles calculation. The appearance of satellite features in the XRD and XRS studies revealed a modulation of the structure along a new 𝑞 vector (0.5,0.5,0) below 120 K. Phonon calculations suggest softening of a phonon mode and a possible superlattice transition at low temperatures. The XANES spectra of the Sn K, Co 𝐿3,2, and Pr 𝑀5,4 edge revealed an increase of charge transfer (CT) at low temperatures as a result of an enhancement of Co3⁢𝑑−Sn5⁢𝑝/Pr⁡4⁢𝑓, and Pr⁡4⁢𝑓−Sn5⁢𝑝 hybridizations. The EXAFS study at the Sn K edge further suggested local distortion of the Sn sites because of Sn-Sn bond elongation at low temperatures. The VB-PES study and theoretical calculations that are based on spin-polarized density functional theory together confirm the strength of hybridization and the lack of any significant change in the band gap of the PCS with temperatures. The RIXS spectra at the Co 𝐿3 edge provide further evidence of the CT process, and the energy level of Co 3⁢𝑑 states below the Fermi level were found to be static in the temperature range of 80 to 300 K, implying no change in the band gap of the PCS with temperatures. Based on the relevant results, the appearance of a clear kink around 138 K in the temperature-dependent specific heat measurements is caused by local lattice distortion at the Sn sites by a diffusionless mechanism, resulting in minimal alteration of the electronic structure through Sn-Sn bond elongation and widening of the Sn-Co-Sn bond angle in PCS. Thus, this study suggests that the system does not undergo a CDW transformation unlike many other similar materials.
關鍵字
語言 en_US
ISSN
期刊性質 國外
收錄於 SCI Scopus
產學合作
通訊作者 Jau-Wern Chiou*,Hung-Chung Hsueh(薛宏中)*, and Way-Faung Pong*
審稿制度 0
國別 USA
公開徵稿
出版型式 ,電子版