Tuning thermal transport in semiconductor nanostructures is of great significance for thermal management in information and power electronics. With excellent transport properties, such as ballistic transport, immunity to point defects and disorders, and forbidden backscattering, topological phonon surface states show remarkable potential in addressing this issue. Herein, topological phonon analyses are performed on hexagonal wurtzite gallium nitride (GaN) to check the topological characteristics of phonons. And other nitrides of the same family, i.e., AlN and AlGaN crystals, are also calculated from a topological phonon phase transition perspective. With the aid of first-principle calculations and topological phonon theory, Weyl phonon states, which host surfaces states without backscattering, are investigated for all these materials. The results show that there is no nontrivial topological phonon state in GaN. However, by introducing Al atoms, i.e., in wurtzite type AlN and AlGaN, more than one Weyl phonon point is found, confirmed by obvious topological characteristics, including non-zero integer topological charges, source/sink in Berry curvature distributions, surface local density of states, and surface arcs. As AlN and AlGaN are typical materials in AlGaN/GaN heterostructure based electronics, the existence of topological phonon states in them will benefit thermal management by facilitating the design of one-way interfacial phonon transport without backscattering.

中文翻译：

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GaN和AlGaN中声子的拓扑效应：调谐声子传输的潜在前景

调整半导体纳米结构中的热传输对信息和电力电子学中的热管理具有重要意义。具有出色的传输性能，例如弹道传输，对点缺陷和异常的免疫力以及禁止的反向散射，拓扑声子表面态在解决此问题方面显示出显着的潜力。在此，对六方纤锌矿型氮化镓（GaN）进行拓扑声子分析，以检查声子的拓扑特性。同样，从拓扑声子相变的角度也可以计算出同一族的其他氮化物，即AlN和AlGaN晶体。借助第一性原理计算和拓扑声子理论，对所有这些材料研究了具有表面状态而无反向散射的Weyl声子状态。结果表明，GaN中不存在非平凡的拓扑声子态。然而，通过引入铝原子，即在纤锌矿型AlN和AlGaN中，发现了一个以上的Weyl声子点，并通过明显的拓扑特征得到了证实，这些特征包括非零整数拓扑电荷，Berry曲率分布的源/宿，表面局部密度。状态和表面弧。由于AlN和AlGaN是基于AlGaN / GaN异质结构的电子器件中的典型材料，因此它们中拓扑声子状态的存在将通过简化单向界面声子传输设计而无反向散射，从而有利于热管理。由明显的拓扑特征（包括非零整数拓扑电荷，Berry曲率分布中的源/汇，状态的表面局部密度和表面弧）确认。由于AlN和AlGaN是基于AlGaN / GaN异质结构的电子器件中的典型材料，因此它们中拓扑声子状态的存在将通过简化单向界面声子传输设计而无反向散射，从而有利于热管理。由明显的拓扑特征（包括非零整数拓扑电荷，Berry曲率分布中的源/汇，状态的表面局部密度和表面弧）确认。由于AlN和AlGaN是基于AlGaN / GaN异质结构的电子器件中的典型材料，因此它们中拓扑声子状态的存在将通过简化单向界面声子传输设计而无反向散射，从而有利于热管理。