The pairing mechanism of high-temperature superconductivity in cuprates is regarded as one of the most challenging issues in condensed matter physics. The core issue concerns how the Cooper pairs are formed. Here we report spin-resolved tunneling measurements on extremely underdoped Bi₂Sr_2−xLa_xCuO_6+δ. Our data reveal that, when holes are doped into the system, the antiferromagnetic order is destroyed, while at the same time an increasing density of states (DOS) peaked at around 200 meV appears within the charge transfer gap. Meanwhile, an electronic structure with 4a₀ × 4a₀ basic plaquettes emerges inhomogeneously, with an area fraction that grows with hole doping. In each plaquette, there are some unidirectional bars (along the Cu-O bond) which are most pronounced at energies near peaks in the DOS around at 25 meV, with an intensity that is especially pronounced at oxygen sites. We argue that the atomically resolved low-energy DOS and related gap are closely associated with some kinds of density waves, possibly reflecting modulations of the electron density, or a pair-density wave, i.e. a modulation of the local pairing. Our work sheds new light on the doping induced electronic evolution from the “parent” insulator of the cuprate superconductors.

铜酸盐中高温超导的配对机制被认为是凝聚态物理中最具挑战性的问题之一。核心问题是库珀对是如何形成的。_{在这里，我们报告了极度欠掺杂的 Bi 2} Sr _{2− x} La _x CuO _6+δ上的自旋分辨隧道测量。我们的数据表明，当空穴掺杂到系统中时，反铁磁序被破坏，同时在电荷转移间隙内出现峰值在 200 meV 左右的增加的状态密度 (DOS)。同时，具有 4 a ₀  × 4 a ₀的电子结构基本的小片不均匀地出现，其面积分数随空穴掺杂而增加。在每个 placette 中，有一些单向条（沿着 Cu-O 键）在 DOS 峰值附近的能量处最明显，大约在 25 meV，其强度在氧位点尤其明显。我们认为，原子分辨的低能 DOS 和相关间隙与某些类型的密度波密切相关，可能反映电子密度的调制，或对密度波，即局部配对的调制。我们的工作为铜酸盐超导体的“母体”绝缘体的掺杂诱导电子演化提供了新的思路。