Abstract The interpretation of the n = 1 image potential state data on graphene on SiC is far from being clarified. In contrast with graphene grown on metallic substrates, graphene on SiC shows a very broad n = 1 image state which is sometimes resolved in two different peaks. In literature the double feature has been ascribed to the presence of a second image state, due to the buffer layer when an incomplete graphene layer occurs, or, alternatively, has been identified as the double series of image states predicted for the free-standing graphene. Here, by varying the pump laser photon energy, in the non-linear photoemission experiment, we are able to reveal the presence of a resonance intensity of the image potential state that in principle could help to shed light on the origin of n = 1 image state on graphene on SiC.

中文翻译：

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碳化硅上石墨烯 n=1 图像势态的共振强度通过双光子光电发射

摘要 对 SiC 上石墨烯的 n = 1 图像势态数据的解释远未阐明。与在金属基板上生长的石墨烯相比，碳化硅上的石墨烯显示出非常宽的 n = 1 图像状态，有时可以分解为两个不同的峰。在文献中，双重特征归因于第二个图像状态的存在，这是由于当不完整的石墨烯层出现时的缓冲层，或者，已被确定为独立石墨烯预测的双重图像状态系列. 在这里，通过改变泵浦激光光子能量，在非线性光电发射实验中，我们能够揭示图像势态共振强度的存在，原则上可以帮助揭示 n = 1 图像的原点碳化硅上石墨烯的状态。