Charge ordering creates a spontaneous array of differently charged ions and is associated with electronic phenomena such as superconductivity, colossal magnetoresistances (CMR), and multiferroicity. Charge orders are usually suppressed by chemical doping and site selective doping of a charge ordered array has not previously been demonstrated. Here we show that selective oxidation of one out of eight distinct Fe²⁺ sites occurs within the complex Fe²⁺/Fe³⁺ ordered structure of 2%-doped magnetite (Fe₃O₄), while the rest of the charge and orbitally ordered network remains intact. This ‘charge order within a charge order’ is attributed to the relative instability of the trimeron distortion surrounding the selected site. Our discovery suggests that similar complex charge ordered arrays could be used to provide surface sites for selective redox reactions, or for storing information by doping specific sites.

电荷有序产生自发的带不同电荷离子的阵列，并与电子现象相关，例如超导性，巨大磁阻（CMR）和多铁性。通常通过化学掺杂抑制电荷顺序，并且以前没有证明电荷有序阵列的位点选择性掺杂。在这里，我们显示了在2个掺杂磁铁矿（Fe ₃ O _4）的复杂Fe ²⁺ / Fe ³⁺有序结构中，八个不同的Fe ²⁺位点之一发生了选择性氧化。），而其余的充电和轨道排序的网络则保持不变。该“充电顺序内的充电顺序”归因于所选位置周围的三聚体畸变的相对不稳定性。我们的发现表明，类似的复杂电荷有序阵列可用于为选择性氧化还原反应提供表面位点，或通过掺杂特定位点来存储信息。