The development of next-generation programmable metasurfaces urgently requires phase change materials with dielectric-metallic transition (DMT-PCMs). Although DMT-PCMs in the infrared have been reported, DMT-PCMs in the visible spectrum are yet to be designed, limiting the nanophotonic applications of conventional programmable metasurfaces to the infrared band. Herein, we find that stoichiometric germanium monotelluride solid solutions, Ge_1-xM_xTe (M = Sn, Sb, Pb, and Bi), have excellent DMT performance throughout the whole visible spectrum, and they can be used as versatile material platforms for fabricating programmable metasurfaces. As a proof-of-concept, the DMT performance of stoichiometric Ge_0.9Sn_0.1Te solid solution is significantly superior to that of commonly studied non-stoichiometric PCMs (e.g., Ge₂Sb₂Te₅, Sb₂Te₃). Through a combination of experiments and first-principle calculations, we demonstrate that the high DMT performance of Ge_0.9Sn_0.1Te derives from the unique bonding structure of the crystalline state with non-stoichiometric vacancy-free, high atomic number, and weak Sn-Te bonds, which is not present in conventional PCMs. Furthermore, using ultrashort-pulse lasers, we show that the crystalline Ge_0.9Sn_0.1Te can be arbitrarily written, erased, and modified at the subwavelength level. The resonance peaks and colors of the Ge_0.9Sn_0.1Te-based grating metasurface can be continuously modulated over the whole visible spectrum. These results suggest that the DMT material platforms can be used to fabricate programmable metasurfaces. Therefore, this work presents a coherent report on the physical origin, material design, and photonic devices of DMT in the visible spectrum, which may extend the applications of programmable metasurfaces from the infrared band to the visible spectrum and inspire more researches.

下一代可编程超表面的开发迫切需要具有介电金属转变（DMT-PCM）的相变材料。尽管已经报道了红外线中的 DMT-PCM，但尚未设计可见光谱中的 DMT-PCM，这将传统可编程超表面的纳米光子应用限制在红外波段。在此，我们发现化学计量的单碲化锗固溶体 Ge _{1- x} M _x Te（M  = Sn、Sb、Pb 和 Bi）在整个可见光谱范围内具有出色的 DMT 性能，可用作多功能材料平台用于制造可编程超表面。作为概念验证，化学计量 Ge _0.9 Sn _{0.1的 DMT 性能}Te 固溶体明显优于通常研究的非化学计量 PCM（例如，Ge ₂ Sb ₂ Te ₅、Sb ₂ Te ₃）。通过实验和第一性原理计算的结合，我们证明了 Ge _0.9 Sn _0.1 Te 的高 DMT 性能源于具有非化学计量空位、高原子序数和弱 Sn- 的晶态独特的键合结构传统 PCM 中不存在的 Te 键。此外，使用超短脉冲激光，我们表明晶体 Ge _0.9 Sn _0.1Te可以在亚波长级别任意写入、擦除和修改。Ge _0.9 Sn _0.1 Te基光栅超表面的共振峰和颜色可以在整个可见光谱范围内连续调制。这些结果表明 DMT 材料平台可用于制造可编程超表面。因此，这项工作对可见光谱中 DMT 的物理起源、材料设计和光子器件进行了连贯的报告，这可能会将可编程超表面的应用从红外波段扩展到可见光谱，并激发更多的研究。