The discovery of graphene with its massless fermions established a new branch of nanomaterials in which linear bands can be realized. It has been predicted that beside Dirac fermions revealing isotropic character and observed in a number of two-dimensional materials, another class of massless fermions can also be found: strongly anisotropic fortune teller-like states which form planes instead of cones in the electronic structure. Here, we demonstrate that such distinct electronic structures exist and can be found in a surface layer of silicon.

中文翻译：

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新型无质量费米子的实验证据

石墨烯及其无质量费米子的发现建立了纳米材料的新分支，其中可以实现线性带。据预测，除了狄拉克费米子具有各向同性特征并在许多二维材料中观察到的外，还可以发现另一类无质量费米子：强各向异性的算命先生状状态，在电子结构中形成平面而不是圆锥形。在这里，我们证明存在这种独特的电子结构，并且可以在硅的表面层中找到它们。