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在单层和双层石墨烯中声子分散的非adiabatic重新规范化

Jiade Li^1,2, Jilin Tang^3,4, Zhiyu Tao^1,5

¹Institute of Physics, Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics and , Beijing 100190, China.

Physical review letters

|July 31, 2025

概括

非adiabatic效应会导致石墨烯异常的声子行为,改变晶格动态. 这项研究揭示了单层和双层石墨烯中新的"W"和"V"形声子分散.

科学领域:

凝聚物质物理学凝聚物质物理学
材料科学材料科学材料科学
频谱学是一种光谱学.

背景情况:

非adiabatic效应显著影响格子动态,导致在布里卢因区 (BZ) 的音声重新规范化.
在低维系统中对这些现象的实验调查是有限的.
了解电子 - 声子合对于新型材料特性至关重要.

研究的目的:

调查单层石墨烯 (MLG) 和伯纳尔双层石墨烯 (BLG) 中的非adiabatic声子分散重规范化.
探索二维材料中非adiabatic效应的维度依赖.
阐明电子 - 声联在异常声行为中的作用.

主要方法:

使用高分辨率电子能量损失光谱法 (HREELS) 来测量声子光谱.
对MLG和BLG进行了全面的测量,遍及整个布里卢恩区 (BZ).
理论分析与实验数据相结合,以解释发现.

主要成果:

在BZ中心附近的MLG中观察到异常的"W"形纵向光学声子分散.
对于BLG,观察到明显的"V"形分散,与传统的抛物线 ("U"形) 分散形成鲜明对比.
这些重新规范化归因于非adiabatic电子-声波合.

结论:

非相应的电子 - 声子合对在石墨烯中观察到的异常声子分散负责.
这项研究提供了对使用MLG和BLG的杂2D系统中非adiabatic效应的比较理解.
这些发现凸显了非adiabatic效应在低维材料的晶格动态中的重要性.

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