Suppression of anharmonicities in crystalline membranes by external strain
Suppression of anharmonicities in crystalline membranes by external strain
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外部应变对结晶膜非谐性的抑制
DOI：
10.1103/physrevb.83.174104
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发表时间：
2011
影响因子：
3.7
通讯作者：
M. Katsnelson
中科院分区：
文献类型：
--
作者：
R. Rold'an;A. Fasolino;K. V. Zakharchenko;M. Katsnelson
在实践中，由于放置物理薄膜的环境，它们会暴露在一定的外部应变(拉伸或压缩)下。结果，膜的声子模的行为被改变。我们发现，在张力的作用下，刚性二维膜中的非谐效应被高度抑制。为此，我们在自洽屏蔽近似(SCSA)中考虑了弯曲模和伸缩模之间的非谐耦合，并将SCSA中得到的高度-高度关联函数与相应的谐和传播子进行了比较。将弹性理论计算结果与原子蒙特卡罗模拟结果进行了比较。我们发现，虽然需要相当高的应变值来避免软膜中的非谐性，但小于1%的应变场足以抑制硬膜中的所有非谐效应，如石墨烯。
In practice, physical membranes are exposed to a certain amount of external strain (tension or compression) due to the environment where they are placed. As a result, the behavior of the phonon modes of the membrane is modified. We show that anharmonic effects in stiff two-dimensional membranes are highly suppressed under the application of tension. For this, we consider the anharmonic coupling between bending and stretching modes in the self-consistent screening approximation (SCSA) and compare the obtained height-height correlation function in the SCSA to the corresponding harmonic propagator. The elasticity theory results are compared to atomistic Monte Carlo simulations for a graphene membrane under tension. We find that, while rather high values of strain are needed to avoid anharmonicity in soft membranes, strain fields less than 1% are enough to suppress all the anharmonic effects in stiff membranes, as graphene.