Riss Alexander, Wickenburg Sebastian, Tan Liang Z, Tsai Hsin-Zon, Kim Youngkyou, Lu Jiong, Bradley Aaron J, Ugeda Miguel M, Meaker Kacey L, Watanabe Kenji, Taniguchi Takashi, Zettl Alex, Fischer Felix R, Louie Steven G, Crommie Michael F
Department of Physics, §Department of Chemical and Biomolecular Engineering, ⊥Department of Chemistry, University of California , Berkeley, California 94720, United States.
ACS Nano. 2014 Jun 24;8(6):5395-401. doi: 10.1021/nn501459v. Epub 2014 May 2.
Gate-controlled tuning of the charge carrier density in graphene devices provides new opportunities to control the behavior of molecular adsorbates. We have used scanning tunneling microscopy (STM) and spectroscopy (STS) to show how the vibronic electronic levels of 1,3,5-tris(2,2-dicyanovinyl)benzene molecules adsorbed onto a graphene/BN/SiO2 device can be tuned via application of a backgate voltage. The molecules are observed to electronically decouple from the graphene layer, giving rise to well-resolved vibronic states in dI/dV spectroscopy at the single-molecule level. Density functional theory (DFT) and many-body spectral function calculations show that these states arise from molecular orbitals coupled strongly to carbon-hydrogen rocking modes. Application of a back-gate voltage allows switching between different electronic states of the molecules for fixed sample bias.
石墨烯器件中载流子密度的栅极控制调谐为控制分子吸附物的行为提供了新机会。我们利用扫描隧道显微镜（STM）和光谱学（STS）展示了吸附在石墨烯/氮化硼/二氧化硅器件上的1,3,5-三（2,2-二氰基乙烯基）苯分子的振动电子能级如何通过施加背栅电压进行调谐。观察到这些分子与石墨烯层发生电子解耦，在单分子水平的dI/dV光谱中产生了分辨率良好的振动状态。密度泛函理论（DFT）和多体光谱函数计算表明，这些状态源于与碳氢摇摆模式强烈耦合的分子轨道。施加背栅电压可在固定样品偏压下实现分子不同电子态之间的切换。
