Phonon angular momentum Hall effect.
Phonon angular momentum Hall effect.
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DOI：
10.1021/acs.nanolett.0c03220
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发表时间：
2020-02
期刊：
影响因子：
10.8
通讯作者：
Sungjoon Park;Bohm-Jung Yang
中科院分区：
文献类型：
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作者：
Sungjoon Park;Bohm-Jung Yang
自旋霍尔效应是电子自旋在外加电场作用下的横向流动。同样，磁体中的温度梯度可以驱动磁振子自旋的横向流动，这为自旋操纵提供了一种热替代方案。最近，声子角动量(PAM)作为一个类似于磁振子自旋的量引起了人们的注意。在这里，我们报道了温度梯度通常会引起PAM的横向流动，我们称之为声子角动量霍尔效应(PAMHE)。当存在横向和纵向声学声子时，PAMHE就会产生，因此它在凝聚态系统中普遍存在。作为PAMHE的结果，PAM在晶体边缘聚集。当晶体中的原子携带非零玻生有效电荷时，边缘PAM产生边缘磁化，这可以通过光学测量观察到。
Spin Hall effect is the transverse flow of the electron spin in response to external electric field. Similarly, temperature gradient in magnets can drive a transverse flow of the magnon spin, which provides a thermal alternative for spin manipulation. Recently, the phonon angular momentum (PAM), the angular momentum of atoms resulting from their orbital motion around their equilibrium positions, has garnered attention as a quantity analogous to the magnon spin. Here, we report that temperature gradient generally induces a transverse flow of PAM, which we term the phonon angular momentum Hall effect (PAMHE). The PAMHE arises whenever there are transverse and longitudinal acoustic phonons, and it is therefore ubiquitous in condensed matter systems. As a consequence of the PAMHE, PAM accumulates at the crystal edges. When the atoms in the crystal carry nonzero Born effective charge, the edge PAM induces edge magnetization, which can be observed through optical measurement.