Fabricating nanoscopic devices capable of manipulating and processing single units of charge is an essential step towards creating functional devices where quantum effects dominate transport characteristics. The archetypal single-electron transistor comprises a small conducting or semiconducting island separated from two metallic reservoirs by insulating barriers^1,2,3,4,5. By enabling the transfer of a well-defined number of charge carriers between the island and the reservoirs, such a device may enable discrete single-electron operations^6,7,8,9. Here, we describe a single-molecule junction comprising a redox-active, atomically precise cobalt chalcogenide cluster wired between two nanoscopic electrodes^10,11. We observe current blockade at room temperature in thousands of single-cluster junctions. Below a threshold voltage, charge transfer across the junction is suppressed. The device is turned on when the temporary occupation of the core states by a transiting carrier is energetically enabled, resulting in a sequential tunnelling process and an increase in current by a factor of ∼600. We perform in situ and ex situ cyclic voltammetry as well as density functional theory calculations to unveil a two-step process mediated by an orbital localized on the core of the cluster in which charge carriers reside before tunnelling to the collector reservoir. As the bias window of the junction is opened wide enough to include one of the cluster frontier orbitals, the current blockade is lifted and charge carriers can tunnel sequentially across the junction.

制造能够操纵和处理单个电荷单位的纳米器件是制造功能器件的重要步骤，在这些器件中，量子效应主导着传输特性。原型单电子晶体管包括一个小的导电或半导电岛，该岛通过绝缘势垒^1,2,3,4,5与两个金属储层隔开。通过使得能够在岛和储层之间转移明确定义数量的电荷载流子，这种装置可以实现离散的单电子操作^6,7,8,9。在这里，我们描述了一个单分子结，包括连接在两个纳米电极^10,11之间的氧化还原活性，原子精确的硫族化物钴簇。。我们观察到室温下数千个单簇结的电流阻塞。低于阈值电压，可抑制跨结的电荷转移。中的装置翻转当由中转载体芯状态的临时占用在能量上启用，从而产生连续的隧道过程和由一个因子的增加的电流〜 600正进行原位和易地循环伏安法以及密度泛函理论计算，揭示了一个由两步过程组成的过程，该过程由位于团簇核心的轨道介导，在该团簇中，电荷载流子在进入收集器储层之前存在于其中。当结的偏置窗口打开得足够宽以包括群集前沿轨道之一时，当前的封锁被解除，电荷载流子可以依次穿过结。