Imaging Field‐Driven Melting of a Molecular Solid at the Atomic Scale
Imaging Field‐Driven Melting of a Molecular Solid at the Atomic Scale
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成像场——原子尺度上分子固体的驱动熔化
DOI：
10.1002/adma.202300542
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发表时间：
2023
影响因子：
29.4
通讯作者：
Zettl, Alex
中科院分区：
文献类型：
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作者：
Liou, Franklin;Tsai, Hsin‐Zon;Goodwin, Zachary A.;Aikawa, Andrew S.;Ha, Ethan;Hu, Michael;Yang, Yiming;Watanabe, Kenji;Taniguchi, Takashi;Zettl, Alex
固-液相变是基本的物理过程，但原子分辨显微镜还没有捕捉到它们的全部动力学。研究人员开发了一种新技术，用于控制石墨烯场效应晶体管（FET）上自组装分子结构的熔化和冻结，该技术允许使用原子分辨扫描隧道显微镜对相变行为进行成像。这是通过在2,3,5,6 -四氟- 7,7,8,8 -四氰喹诺二甲烷修饰的FET上施加电场来诱导FET表面分子固相和液相之间的可逆转变来实现的。通过电流快速加热石墨烯衬底并成像导致新的二维平衡态的演变，可以可视化非平衡熔化动力学。建立了一个分析模型，解释了基于固体和液体分子能级的光谱测量所观察到的混合态相。观测到的非平衡熔融动力学与蒙特卡罗模拟结果一致。
Solid–liquid phase transitions are basic physical processes, but atomically resolved microscopy has yet to capture their full dynamics. A new technique is developed for controlling the melting and freezing of self‐assembled molecular structures on a graphene field‐effect transistor (FET) that allows phase‐transition behavior to be imaged using atomically resolved scanning tunneling microscopy. This is achieved by applying electric fields to 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane‐decorated FETs to induce reversible transitions between molecular solid and liquid phases at the FET surface. Nonequilibrium melting dynamics are visualized by rapidly heating the graphene substrate with an electrical current and imaging the resulting evolution toward new 2D equilibrium states. An analytical model is developed that explains observed mixed‐state phases based on spectroscopic measurement of solid and liquid molecular energy levels. The observed nonequilibrium melting dynamics are consistent with Monte Carlo simulations.