发表机构
Xiangtan University; Key Laboratory of Computational Condensed Matter Physics and Materials Quantum Engineering of Hunan Provincial Universities, Xiangtan University（湘潭大学; 湖南省高校计算凝聚态物理与材料量子工程重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过声子局域化解耦晶格热导率的类粒子与类波输运通道，在准一维三元螺旋晶体中实现了创纪录的低热导率，为探索晶体热导率极限提供了关键思路。
AI 中文摘要
将无机晶体固体的本征晶格热导率推向其最低极限的一个基本瓶颈，源于类粒子传播（κ_L^P）与类波隧穿（κ_L^C）通道之间的固有竞争。本文证明，声子局域化为解耦双通道输运提供了可靠途径，在准一维三元螺旋晶体中实现了创纪录的低κ_L。尽管结构复杂性导致声子支密集分布，进而产生大量相干声子，但弱链间相互作用与重元素将众多声子支压缩为高度局域化、几乎无色散的平带。这种强局域化同时抑制了群速度的对角和非对角分量，从而协同抑制κ_L^P与κ_L^C。以InSeI为例，室温下的链间κ_L^P与κ_L^C分别为0.145 W/mK和0.053 W/mK，总κ_L低至0.198 W/mK。GaSeI与AlSeI的链间相互作用更弱，室温κ_L分别达创纪录的0.086 W/mK与0.089 W/mK，900 K时更是降至0.058 W/mK与0.059 W/mK。这些发现为探索晶体热导率极限提供了重要见解。
英文摘要
A fundamental bottleneck in pushing the intrinsic lattice thermal conductivity of inorganic crystalline solids to its lowest limit arises from the inherent competition between the particle-like propagation (\(κ_{\mathrm{L}}^{\mathrm{P}}\)) and wave-like tunneling (\(κ_{\mathrm{L}}^{\mathrm{C}}\)) channels. Herein, we demonstrate that phonon localization provides a robust pathway to decouple the dual-channel transport, achieving record-low \(κ_{\mathrm{L}}\) in quasi-1D ternary helical crystals. Despite the structural complexity leading to densely populated phonon branches and thus inducing abundant coherent phonons, the weak interchain interactions and heavy elements compress numerous branches into highly localized, nearly dispersionless flat bands. Such strong localization simultaneously suppresses both the diagonal and off-diagonal components of the group velocity, thereby synergistically suppressing \(κ_{\mathrm{L}}^{\mathrm{P}}\) and \(κ_{\mathrm{L}}^{\mathrm{C}}\). Taking InSeI as an example, the interchain room-temperature \(κ_{\mathrm{L}}^{\mathrm{P}}\) and \(κ_{\mathrm{L}}^{\mathrm{C}}\) are 0.145 and 0.053 W/mK, respectively, yielding an ultralow total \(κ_{\mathrm{L}}\) of 0.198 W/mK. Weaker interchain interactions further drive the room-temperature \(κ_{\mathrm{L}}\) of GaSeI and AlSeI to record lows of 0.086 and 0.089 W/mK, respectively; these values even drop to 0.058 and 0.059 W/mK at 900 K. These findings provide useful insights into exploring the thermal conductivity limit in crystals.
