The path from a Mott insulating phase to high temperature superconductivity encounters a rich set of unconventional phenomena involving the insulator-to-metal transition (IMT), such as emergent electronic orders and pseudogaps, that ultimately affect the condensation of Cooper pairs. A huge hindrance to understanding the origin of these phenomena is the difficulty in accessing doping levels near the parent state. The J_eff = 1/2 Mott state of the perovskite strontium iridates has revealed intriguing parallels to the cuprates, with the advantage that it provides unique access to the Mott transition. Here, we exploit this accessibility to study the IMT and the possible nearby electronic orders in the electron-doped bilayer iridate (Sr_1 − xLa_x)₃Ir₂O₇. Using spectroscopic imaging scanning tunneling microscopy, we image the La dopants in the top as well as the interlayer SrO planes. Surprisingly, we find a disproportionate distribution of La between these layers with the interlayer La being primarily responsible for the IMT. This reveals the distinct site-dependent effects of dopants on the electronic properties of bilayer systems. Electron doping also results in charge reordering. We find unidirectional electronic order concomitant with the structural distortion known to exist in this system. Intriguingly, similar to the single layer iridate, we also find local resonant states forming a checkerboard-like pattern trapped by La. This suggests that multiple charge orders may exist simultaneously in Mott systems, even with only one band crossing the Fermi energy.

从莫特绝缘相到高温超导的路径遇到了一系列涉及绝缘子到金属的过渡（IMT）的非常规现象，例如新兴的电子阶和伪间隙，最终会影响库珀对的缩合。理解这些现象的起源的巨大障碍是难以获得母体状态附近的掺杂水平。 钙钛矿铱酸盐的J _eff = 1/2莫特态显示出与铜酸盐有趣的相似之处，其优点是它提供了进入莫特转变的独特途径。在这里，我们利用这种可访问性来研究IMT和电子掺杂双层铱酸盐（Sr _1-x La _x）中可能的附近电子阶。₃ Ir ₂ O ₇。使用光谱成像扫描隧道显微镜，我们在顶部以及层间SrO平面中对La掺杂剂成像。出乎意料的是，我们发现这些层之间的La分布不成比例，而中间层La主要负责IMT。这揭示了掺杂剂对双层系统的电子性质的明显的位置依赖性效应。电子掺杂还导致电荷重新排序。我们发现与该系统中已知存在的结构失真相伴的单向电子顺序。有趣的是，类似于单层铱酸盐，我们还发现了局部共振态，形成被La俘获的棋盘状图案。这表明，即使只有一个能带穿过费米能量，在Mott系统中也可能同时存在多个电荷级。