论文标题
模式定位并抑制无定形合金的热传输
Mode Localization and Suppressed Heat Transport in Amorphous Alloys
论文作者
论文摘要
玻璃通常代表固体导热率的下限，但是对无定形材料的晶格热传输的基本了解可以提供设计规则以击败这种极限。 Here we investigate the role of mass disorder in glasses by studying amorphous silicon-germanium alloy (a-Si$_{1-x}$Ge$_x$) over the full range of atomic concentration from $x=0$ to $x=1$, using molecular dynamics and the quasi-harmonic Green-Kubo lattice dynamics formalism.我们发现，作为$ x $的函数，A-Si $ _ {1-X} $ ge $ _x $的热导率与Crystalline Mass-disorder-disordery合金相比，$ x $的函数表现出更光滑的U形。低ge浓度下热导率初始下降的主要贡献源于原本扩展模式的定位，该模式构成了最低8％\％人口的频率。随着GE的增加，中等频率模式的贡献逐渐逐渐降低，以达到GE浓度之间的宽最小导热率，从$ x = 0.25 $降至0.75美元。
Glasses usually represent the lower limit for the thermal conductivity of solids, but a fundamental understanding of lattice heat transport in amorphous materials can provide design rules to beat such a limit. Here we investigate the role of mass disorder in glasses by studying amorphous silicon-germanium alloy (a-Si$_{1-x}$Ge$_x$) over the full range of atomic concentration from $x=0$ to $x=1$, using molecular dynamics and the quasi-harmonic Green-Kubo lattice dynamics formalism. We find that the thermal conductivity of a-Si$_{1-x}$Ge$_x$ as a function of $x$ exhibits a smoother U-shape than in crystalline mass-disordered alloys. The main contribution to the initial drop of thermal conductivity at low Ge concentration stems from the localization of otherwise extended modes that make up the lowest 8\% of the population by frequency. Contributions from intermediate frequency modes are decreased more gradually with increasing Ge to reach a broad minimum thermal conductivity between concentrations of Ge from $x=0.25$ to $0.75$.
