论文标题
内部压力和定位的最小络合物产生类似玻璃的非调音激发
Internally-stressed and positionally-disordered minimal complexes yield glasslike nonphononic excitations
论文作者
论文摘要
眼镜与晶体的同类产品不同，表现出低频的非音型激发，其频率$ω$遵循通用$ \ MATHCAL {d} \！\ left（ω\ right（ω\ right）\！\ sim \ sim \！ω^4 $的状态密度。玻璃形成的过程会产生与机械挫败感交织在一起的位置障碍，从而在理解玻璃质非phononic激发的起源方面构成了基本挑战。在这里，我们建议\ emph {Minimal Complextes} - 机械填充和定位的局部结构 - 体现了产生玻璃状激发所需的最小物理成分。我们研究了机械挫败感和位置障碍对孤立最小复合物振动光谱的个体影响，并证明了边缘稳定的最小络合物的集合产生$ \ MATHCAL {d} \！\！\！\！此外，通过将单个最小复合物嵌入完美的晶格中，出现了玻璃状激发。因此，最小的复合物提供了一个概念框架，可以从第一原理中了解玻璃般的激发，以及将它们引入固体中的实用计算方法。
Glasses, unlike their crystalline counterparts, exhibit low-frequency nonphononic excitations whose frequencies $ω$ follow a universal $\mathcal{D}\!\left(ω\right)\!\sim\!ω^4$ density of states. The process of glass formation generates positional disorder intertwined with mechanical frustration, posing fundamental challenges in understanding the origins of glassy nonphononic excitations. Here we suggest that \emph{minimal complexes} -- mechanically-frustrated and positionally-disordered local structures -- embody the minimal physical ingredients needed to generate glasslike excitations. We investigate the individual effects of mechanical frustration and positional disorder on the vibrational spectrum of isolated minimal complexes, and demonstrate that ensembles of marginally stable minimal complexes yield $\mathcal{D}\!\left(ω\right)\!\sim\!ω^4$. Furthermore, glasslike excitation emerge by embedding a single minimal complex within a perfect lattice. Consequently, minimal complexes offer a conceptual framework to understand glasslike excitations from first principles, as well as a practical computational method for introducing them into solids.
