Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de Bellaterra, 08193 Barcelona, Spain.
Phys Rev Lett. 2010 May 7;104(18):185701. doi: 10.1103/PhysRevLett.104.185701. Epub 2010 May 3.
We report large-scale first-principles simulations of melting of four different phases of Li at pressures ranging from 0 to 50 GPa. We find excellent agreement with existing experimental data at low pressures, and confirm that above 10 GPa the melting line develops a negative slope, in parallel to what occurs for Na at 30 GPa. Surprisingly, our results indicate that the melting temperature of the bcc phase is always higher than that of fcc Li, suggesting the intriguing possibility of the existence of a narrow field of bcc stability separating the fcc and liquid phases, as predicted by Alexander and McTague [Phys. Rev. Lett. 41, 702 (1978)].
我们报告了在 0 到 50 GPa 的压力范围内对四种不同相的 Li 的熔化进行的大规模第一性原理模拟。我们在低压力下与现有的实验数据吻合得非常好，并证实了在 10 GPa 以上，熔化线呈现出负斜率，与 30 GPa 时的 Na 情况平行。令人惊讶的是，我们的结果表明 bcc 相的熔化温度总是高于 fcc Li，这表明存在一个狭窄的 bcc 稳定场的可能性，将 fcc 和液态相分开，正如 Alexander 和 McTague [Phys. Rev. Lett. 41, 702 (1978)]所预测的那样。
