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arXiv 2209.05033cond-mat.mtrl-scicond-mat.mes-hallphysics.app-phphysics.comp-ph
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声子角动量由温度和应变驱动的发散行为

Divergent phonon angular momentum driven by temperature and strain

Young-Jae Choi, Seung-Hoon Jhi

AI总结:

本研究通过第一性原理计算,发现AlN、GaN及g-BN单层的声子角动量在低温或应变下可发散,为旋转激发的力学与热学调控提供了可能。

摘要:

声子角动量(PAM)可能表现出奇特的温度依赖性,因为它对声子寿命敏感。恒定声子寿命近似无法描述这种行为。在此,我们通过第一性原理计算,在充分考虑声子寿命的情况下,研究了AlN、GaN和类石墨烯氮化硼(g-BN)单层的PAM。我们表明,纤锌矿结构的AlN和GaN在低温下从其最低声子支获得发散的PAM。另一方面,g-BN单层在平衡结构下不具有有限的PAM。相反,它在PAM中表现出有趣的应变依赖性;大于临界尺寸的压缩应变由于TA声子的发散寿命而在低温下产生发散的PAM。由于PAM与固体中与电荷、自旋或电磁场相关的旋转激发耦合,我们的研究展示了对此类激发进行力学和热学工程调控的可能性。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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