论文标题
由温度和应变驱动的发散声子角动量
Divergent phonon angular momentum driven by temperature and strain
论文作者
论文摘要
声子角动量（PAM）可能表现出异国情调的温度依赖性，因为它对声子寿命很敏感。恒定的语音寿命近似无法描述这种行为。在这里，我们使用第一原理计算研究了ALN，GAN和石墨烯样氮化硼（G-BN）单层的PAM，并完全考虑了声子寿命。我们表明，Wurtzite Aln和Gan在低温下从其最低的声子分支中获取了发散的PAM。另一方面，G-BN单层在平衡结构下没有有限的PAM。相反，它显示出PAM中的菌株依赖性。大于临界尺寸的压缩应变由于TA声子的不同寿命在低温下会产生不同的PAM。作为与电荷，自旋或电磁场相关的固体旋转激发的PAM夫妇，我们的研究表明了这种激发的机械和热工程的可能性。
The phonon angular momentum (PAM) may exhibit exotic temperature dependence as it is sensitive to the phonon lifetime. Constant phonon-lifetime approximation fails to depict such behavior. Here, we study the PAM of AlN, GaN, and graphene-like boron nitride (g-BN) monolayer with full consideration of phonon lifetime using first-principles calculations. We show that wurtzite AlN and GaN acquire divergent PAM at low temperatures from their lowest-lying phonon branches. The g-BN monolayer, on the other hand, does not have finite PAM at equilibrium structure. Rather it shows intriguing strain-dependence in PAM; the compressive strain greater than the critical size generates divergent PAM at low temperatures due to the divergent lifetime of TA phonons. As PAM couples with rotational excitations in solids associated with charge, spin, or electromagnetic fields, our study demonstrates a possibility of mechanical and thermal engineering of such excitations.
