State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
Nat Commun. 2013;4:1365. doi: 10.1038/ncomms2369.
Although the mechanism of superconductivity in the cuprates remains elusive, it is generally agreed that at the heart of the problem is the physics of doped Mott insulators. A crucial step for solving the high temperature superconductivity puzzle is to elucidate the electronic structure of the parent compound and the behaviour of doped charge carriers. Here we use scanning tunnelling microscopy to investigate the atomic-scale electronic structure of the Ca(2)CuO(2)Cl(2) parent Mott insulator of the cuprates. The full electronic spectrum across the Mott-Hubbard gap is uncovered for the first time, which reveals the particle-hole symmetric and spatially uniform Hubbard bands. Defect-induced charge carriers are found to create broad in-gap electronic states that are strongly localized in space. We show that the electronic structure of pristine Mott insulator is consistent with the Zhang-Rice singlet model, but the peculiar features of the doped electronic states require further investigations.
虽然铜氧化物超导体的超导机制仍然难以捉摸，但人们普遍认为，问题的核心是掺杂莫特绝缘体的物理学。解决高温超导难题的关键步骤是阐明母体化合物的电子结构和掺杂电荷载流子的行为。在这里，我们使用扫描隧道显微镜来研究铜氧化物的钙（2）铜（O）（2）氯（2）母体莫特绝缘体的原子尺度电子结构。首次揭示了整个莫特-哈伯德隙中的全电子谱，揭示了粒子-空穴对称且空间均匀的哈伯德带。发现缺陷诱导的载流子产生了宽的带隙电子态，这些电子态在空间中强烈局域。我们表明，原始莫特绝缘体的电子结构与张-赖斯单重态模型一致，但掺杂电子态的特殊特征需要进一步研究。
