论文标题
硫酸铵中原子动力学的压力依赖性：ii。振动
Pressure dependence of atomic dynamics in barocaloric ammonium sulfate: II. Vibrations
论文作者
论文摘要
硫酸铵是一种巨大的逆向金属材料，廉价且可商购。利用其冷却应用的潜力需要了解驱动熵变化的机制。在这里，我们报告了在温度和压力的工作条件下对声子的非弹性中子散射和密度功能理论进行的研究。我们发现实验结果和计算结果之间有着极好的一致性。对于熵变化至关重要的铵图书馆模式可以通过其负格尼森参数来识别。我们的结果将整个相过渡的结构差异与原子动力学中的结构差异联系在一起，这表明设计了新的热量材料。
Ammonium sulfate is a giant inverse barocaloric material that is cheaply and commercially available. Exploiting its potential for cooling applications requires an understanding of the mechanism driving the entropy change. Here we report an investigation by inelastic neutron scattering and density functional theory of the phonons under working conditions of temperature and pressure. We find excellent agreement between the experimental and calculated results. The ammonium librational modes that are crucial to the entropy change are identifiable by their negative Grüneisen parameter. Our results connect the differences in structure across the phase transition to those in the atomic dynamics, suggesting a route towards designing new caloric materials.
