Department of Chemistry and Chemical Biology and ‡Laboratory of Atomic and Solid State Physics, Cornell University Ithaca, New York 14853, United States.
J Am Chem Soc. 2017 Jun 28;139(25):8740-8751. doi: 10.1021/jacs.7b04456. Epub 2017 Jun 19.
In a search for gold hydrides, an initial discouraging result of no theoretical stability in any binary AuH at P < 300 GPa was overcome by introducing alkali atoms as reductants. A set of AAuH compounds, A = Li, Na, K, Rb, and Cs, is examined; of these, certain K, Rb, and Cs compounds are predicted to be thermodynamically stable. All contain AuH molecular units and are semiconducting at P = 1 atm, and some form metallic and superconducting symmetrically bonded AuHAu sheets under compression. To induce metallicity by bringing the Au atoms closer together under ambient conditions, we examined alkaline earth ion substitution for two A, i.e., materials of composition AE(AuH). For AE = Ba and Sr, the materials are already marginally metallic at P = 1 atm and the combination of high and low phonon frequencies and good electron-phonon coupling leads to reasonably high calculated superconducting transition temperatures for these materials.
在寻找金氢化物的过程中，由于在 P < 300 GPa 下任何二元 AuH 的理论稳定性都没有，最初的结果令人沮丧，但通过引入碱金属原子作为还原剂克服了这一问题。本文研究了一组 AAuH 化合物，A = Li、Na、K、Rb 和 Cs；其中，某些 K、Rb 和 Cs 化合物被预测是热力学稳定的。所有这些化合物都含有 AuH 分子单元，在 P = 1 atm 下是半导体，并且在压缩下某些化合物形成金属和超导对称键合的 AuHAu 片。为了通过在环境条件下使 Au 原子更接近来诱导金属性，我们研究了两种 A 的碱土金属离子取代，即组成 AE(AuH)的材料。对于 AE = Ba 和 Sr，这些材料在 P = 1 atm 时已经略微具有金属性，并且高和低声子频率的组合以及良好的电子-声子耦合导致这些材料的计算超导转变温度相当高。
