Shenzhen Institute for Quantum Science and Engineering (SIQSE) and Department of Physics, Southern University of Science and Technology (SUSTech), 518055, Shenzhen, Guangdong, China.
International Quantum Academy, 518048, Shenzhen, Guangdong, China.
Nat Commun. 2023 May 22;14(1):2905. doi: 10.1038/s41467-023-38589-0.
The century-long development of surface sciences has witnessed the discoveries of a variety of quantum states. In the recently proposed "obstructed atomic insulators", symmetric charges are pinned at virtual sites where no real atoms reside. The cleavage through these sites could lead to a set of obstructed surface states with partial electronic occupation. Here, utilizing scanning tunneling microscopy, angle-resolved photoemission spectroscopy and first-principles calculations, we observe spectroscopic signature of obstructed surface states in SrInP. We find that a pair of surface states that are originated from the pristine obstructed surface states split in energy by a unique surface reconstruction. The upper branch is marked with a striking differential conductance peak followed by negative differential conductance, signaling its localized nature, while the lower branch is found to be highly dispersive. This pair of surface states is in consistency with our calculational results. Our finding not only demonstrates a surface quantum state induced by a new type of bulk-boundary correspondence, but also provides a platform for exploring efficient catalysts and related surface engineering.
表面科学的百年发展见证了各种量子态的发现。在最近提出的“受阻原子绝缘体”中，对称电荷被固定在没有实际原子存在的虚拟位置。通过这些位置的劈裂可能会导致一组具有部分电子占据的受阻表面态。在这里，我们利用扫描隧道显微镜、角分辨光发射光谱和第一性原理计算，在 SrInP 中观察到受阻表面态的光谱特征。我们发现，一对源自原始受阻表面态的表面态在能量上由于独特的表面重构而分裂。上分支带有显著的微分电导峰，随后是负微分电导，表明其局域性质，而下分支则被发现具有高度的色散性。这一对表面态与我们的计算结果一致。我们的发现不仅证明了由新型体-边对应关系引起的表面量子态，而且为探索高效催化剂和相关表面工程提供了一个平台。
