The Formation of Warm Dense Matter: Experimental Evidence for Electronic Bond Hardening in Gold
The Formation of Warm Dense Matter: Experimental Evidence for Electronic Bond Hardening in Gold
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DOI：
10.1126/science.1162697
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发表时间：
2009-02-20
期刊：
影响因子：
56.9
通讯作者：
Miller, R. J. Dwayne
中科院分区：
文献类型：
--
作者：
Ernstorfer, Ralph;Harb, Maher;Miller, R. J. Dwayne
在强光激发条件下，有可能产生高度非平衡态的物质。核响应由从激发电子到原子核的能量转移速率和电子分布变化对原子间势能景观的瞬时影响决定。我们使用飞秒电子衍射跟踪强激发态金在这些瞬态电子条件下的结构演化。一般来说，材料在受到激励时会变得更软。相比之下，发现金晶格的无序速率在激发水平高达2.85兆焦耳/千克时相对于晶格加热的程度被延迟，这表明在高有效电子温度下晶格稳定性增加，这是一种预测的效果，说明了电子结构和晶格键合之间的强相关性。
Under strong optical excitation conditions, it is possible to create highly nonequilibrium states of matter. The nuclear response is determined by the rate of energy transfer from the excited electrons to the nuclei and the instantaneous effect of change in electron distribution on the interatomic potential energy landscape. We used femtosecond electron diffraction to follow the structural evolution of strongly excited gold under these transient electronic conditions. Generally, materials become softer with excitation. In contrast, the rate of disordering of the gold lattice is found to be retarded at excitation levels up to 2.85 megajoules per kilogram with respect to the degree of lattice heating, which is indicative of increased lattice stability at high effective electronic temperatures, a predicted effect that illustrates the strong correlation between electronic structure and lattice bonding.