Phonon transition across an isotopic interface

Autor: Ning Li, Ruochen Shi, Yifei Li, Ruishi Qi, Fachen Liu, Xiaowen Zhang, Zhetong Liu, Yuehui Li, Xiangdong Guo, Kaihui Liu, Ying Jiang, Xin-Zheng Li, Ji Chen, Lei Liu, En-Ge Wang, Peng Gao
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Nature Communications, Vol 14, Iss 1, Pp 1-7 (2023)
Druh dokumentu: article
ISSN: 2041-1723
DOI: 10.1038/s41467-023-38053-z
Popis: Abstract Isotopic mixtures result in distinct properties of materials such as thermal conductivity and nuclear process. However, the knowledge of isotopic interface remains largely unexplored mainly due to the challenges in atomic-scale isotopic identification. Here, using electron energy-loss spectroscopy in a scanning transmission electron microscope, we reveal momentum-transfer-dependent phonon behavior at the h−10BN/h-11BN isotope heterostructure with sub-unit-cell resolution. We find the phonons’ energy changes gradually across the interface, featuring a wide transition regime. Phonons near the Brillouin zone center have a transition regime of ~3.34 nm, whereas phonons at the Brillouin zone boundary have a transition regime of ~1.66 nm. We propose that the isotope-induced charge effect at the interface accounts for the distinct delocalization behavior. Moreover, the variation of phonon energy between atom layers near the interface depends on both of momentum transfer and mass change. This study provides new insights into the isotopic effects in natural materials.
Databáze: Directory of Open Access Journals