Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
Phys Rev Lett. 2013 Apr 26;110(17):178002. doi: 10.1103/PhysRevLett.110.178002.
The mechanical response of solids depends on temperature, because the way atoms and molecules respond collectively to deformation is affected at various levels by thermal motion. This is a fundamental problem of solid state science and plays a crucial role in materials science. In glasses, the vanishing of shear rigidity upon increasing temperature is the reverse process of the glass transition. It remains poorly understood due to the disorder leading to nontrivial (nonaffine) components in the atomic displacements. Our theory explains the basic mechanism of the melting transition of amorphous (disordered) solids in terms of the lattice energy lost to this nonaffine motion, compared to which thermal vibrations turn out to play only a negligible role. The theory is in good agreement with classic data on melting of amorphous polymers (for which no alternative theory can be found in the literature) and offers new opportunities in materials science.
固体的力学响应取决于温度，因为原子和分子集体对变形的响应方式在不同层次上受到热运动的影响。这是固体科学的一个基本问题，在材料科学中起着至关重要的作用。在玻璃中，随着温度的升高剪切刚性的消失是玻璃转变的反向过程。由于无序导致原子位移出现非平凡（非仿射）分量，因此该过程仍未得到很好的理解。与热振动相比，我们的理论根据晶格能的损失来解释无定形（无序）固体的熔融转变的基本机制，这种能量损失归因于这种非仿射运动。该理论与无定形聚合物的熔融的经典数据吻合良好（文献中找不到其他替代理论），并为材料科学提供了新的机会。
