Chakraborty Surajit, Krishnan Vishnu V, Ramola Kabir, Karmakar Smarajit
Tata Institute of Fundamental Research, Hyderabad, 500046 Telangana, India.
PNAS Nexus. 2023 Sep 5;2(9):pgad289. doi: 10.1093/pnasnexus/pgad289. eCollection 2023 Sep.
We show through simulations of amorphous solids prepared in open-boundary conditions that they possess significantly fewer low-frequency vibrational modes compared to their periodic boundary counterparts. Specifically, using measurements of the vibrational density of states, we find that the law changes to with in two dimensions and in three dimensions. Crucially, this enhanced stability is achieved when utilizing slow annealing protocols to generate solid configurations. We perform an anharmonic analysis of the minima corresponding to the lowest frequency modes in such open-boundary systems and discuss their correlation with the density of states. A study of various system sizes further reveals that small systems display a higher degree of localization in vibrations. Lastly, we confine open-boundary solids in order to introduce macroscopic stresses in the system, which are absent in the unconfined system and find that the behavior is recovered.
我们通过对在开放边界条件下制备的非晶态固体进行模拟表明,与具有周期性边界的对应物相比,它们拥有显著更少的低频振动模式。具体而言,通过测量振动态密度,我们发现在二维中定律变为 ,在三维中变为 。至关重要的是,当利用缓慢退火协议来生成固体构型时可实现这种增强的稳定性。我们对这种开放边界系统中对应于最低频率模式的极小值进行了非谐分析,并讨论了它们与态密度的相关性。对各种系统尺寸的研究进一步表明,小系统在振动中表现出更高程度的局域化。最后,我们对开放边界固体进行限制,以便在系统中引入宏观应力,而在无限制系统中不存在这种应力,并发现 行为得以恢复。