Phase change memory has been developed into a mature technology capable of storing information in a fast and non-volatile way^1,2,3, with potential for neuromorphic computing applications^4,5,6. However, its future impact in electronics depends crucially on how the materials at the core of this technology adapt to the requirements arising from continued scaling towards higher device densities. A common strategy to fine-tune the properties of phase change memory materials, reaching reasonable thermal stability in optical data storage, relies on mixing precise amounts of different dopants, resulting often in quaternary or even more complicated compounds^6,7,8. Here we show how the simplest material imaginable, a single element (in this case, antimony), can become a valid alternative when confined in extremely small volumes. This compositional simplification eliminates problems related to unwanted deviations from the optimized stoichiometry in the switching volume, which become increasingly pressing when devices are aggressively miniaturized^9,10. Removing compositional optimization issues may allow one to capitalize on nanosize effects in information storage.

相变存储器已经发展成为一种成熟的技术，能够以快速，非易失的方式^1,2,3存储信息，具有神经形态计算应用^4,5,6的潜力。但是，它对电子学的未来影响在很大程度上取决于该技术核心材料如何适应不断向更高的器件密度扩展的要求。一种微调相变存储材料的特性，以在光学数据存储中达到合理的热稳定性的通用策略，依赖于混合精确量的不同掺杂剂，从而经常导致四元或更复杂的化合物^6,7,8。在这里，我们展示了可以想象的最简单的材料，即单一元素（在这种情况下为锑），当被限制在极小的体积中时如何成为有效的替代品。这种简化的结构消除了与开关量中最佳化学计量比产生的不希望有的偏差有关的问题，当器件被积极地小型化^9,10时，这种偏差变得越来越紧迫。消除成分优化问题可以使人们利用信息存储中的纳米级效应。