Abstract Manipulation of thermal fluxes is essential in today’s science and technology. However, modern thermal phononics rely on the wave interference of phonons and thus are truly efficient either at sub-kelvin temperatures or atomic scales. We propose an alternative concept of heat manipulation based on the particle picture of phonons and their ballistic transport. We call this concept ray phononics as a thermal analogy of ray optics. Ray phononics is free from limitations of the traditional phononics and enables creating and guiding thermal fluxes in realistic nanostructures regardless of their surface roughness. Our simulations illustrate possible application of ray phononics for emitting directional heat rays, filtering the phonon spectrum, and even protecting a specific region from a thermal gradient. Finally, we show that the proposed concept is not bound to only low temperatures, and ray-phononic nanostructures can control heat fluxes even at room temperature using modern materials like boron arsenide.

中文翻译：

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射线声子：由弹道声子传输驱动的热导、发射器、过滤器和屏蔽

摘要 在当今的科学技术中，热通量的处理是必不可少的。然而，现代热声子学依赖于声子的波干涉，因此在亚开尔文温度或原子尺度下都是真正有效的。我们提出了一种基于声子及其弹道传输的粒子图像的热操纵的替代概念。我们称这个概念为射线声子学作为射线光学的热类比。射线声子不受传统声子的限制，无论表面粗糙度如何，都可以在现实的纳米结构中创建和引导热通量。我们的模拟说明了射线声子学在发射定向热射线、过滤声子谱甚至保护特定区域免受热梯度影响方面的可能应用。最后，