Dynamics of rare-gas floating monolayers in the self-consistent phonon theory.
Dynamics of rare-gas floating monolayers in the self-consistent phonon theory.
复制标题
自洽声子理论中稀有气体漂浮单分子层的动力学。
DOI：
10.1103/physrevb.34.2815
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Chui
中科院分区：
文献类型：
--
作者：
Moleko;Joós;Hakim;Glyde;Chui
利用自洽声子理论，研究了不同晶格间距和温度下，氘、氪、氩和氖的二维浮动单分子膜的动力学行为。计算了T =0 K时的声子色散曲线和零点能，并估算了合适的德拜温度和均方根振动振幅（u ~ 2）。结果表明，Ar和Ar的浮动单分子膜很好地代表了它们的物理吸附对应物。结果还表明，Ne和Kr在T &25K时是有效的简谐晶体，而Ne在所有T时都是强非简谐的二维晶体。Ne在T =0 K时的自洽谐波频率几乎是谐波值的两倍。Ar是中间情况。有效德拜温度为ea-65 K，林德曼比y =（u '）/R在0 K时从3%（Nd）到9%（Ne），与三维晶体值相似。声子频率对晶格参数和温度的依赖性比3D晶体更敏感。
The dynamics of floating two-dimensional {2D) monolayers of Xe, Kr, Ar, and Ne are explored over a range of lattice spacings and temperature using the self-consistent phonon theory. Phonon dispersion curves and the zero-point energy are calculated and appropriate Debye temperatures and rms vibrational amplitudes (u2) estimated at T =0 K. The results show that floating monolayers of Ar and Xe represent their physisorbed counterparts well. They also show that Xe and Kr are effectively harmonic at T &25 K while Ne is a strongly anharmonic 2D crystal at all T. The selfconsistent harmonic frequencies in Ne at T =0 K are nearly twice the harmonic values. Ar is an intermediate case. The effective Debye temperature is ea -65 K in all cases and the Lindemann ratio y = (u ') /R varies from 3% in Xe to 9% in Ne at T =0 K, similar to 3D crystal values. The phonon frequencies depend sensitively on lattice parameter and temperature, more so than in 3D crystals.