论文标题
手性诱导的声子分散在非中心微极晶体中
Chirality-induced Phonon Dispersion in a Noncentrosymmetric Micropolar Crystal
论文作者
论文摘要
在微极弹性理论中检查了手性晶体的声子频谱的特征。这种形式主义不仅解释了介质的翻译微功能，还解释了旋转的微功能。发现在纯粹的声子扇形中的左/右圆极化而没有调用任何外部子系统，就会出现声子板分裂。声子频谱揭示了平等的破裂，同时保留了时间反向对称性，即具有真正的手性。我们发现，微旋转和翻译模式的杂交产生了声音声子分支，“旋转”最小使人联想到超流体氦气中的基本激发。我们认为，这种现象的机制与Nozières的重新解释一致[J.低温。物理。 \ textbf {137}，45（2004）]，作为初始结晶不稳定性的表现。我们讨论了微极弹性介质与Bogoliubov准粒子中的平移和旋转微功能之间的一个类比，以及$ {}^{4} $ He中的差异密度波动。
Features of the phonon spectrum of a chiral crystal are examined within the micropolar elasticity theory. This formalism accounts for not only translational micromotions of a medium but also rotational ones. It is found that there appears the phonon band splitting depending on the left/right-circular polarization in a purely phonon sector without invoking any outside subsystem. The phonon spectrum reveals parity breaking while preserving time-reversal symmetry, i.e. it possesses true chirality. We find that hybridization of the micro-rotational and translational modes gives rise to the acoustic phonon branch with a "roton" minimum reminiscent of the elementary excitations in the superfluid helium-4. We argue that a mechanism of this phenomena is in line with Nozières' reinterpretation [J. Low Temp. Phys. \textbf{137}, 45 (2004)] of the rotons as a manifistation of an incipient crystallization instability. We discuss a close analogy between the translational and rotational micromotions in the micropolar elastic medium and the Bogoliubov quasiparticles and gapful density fluctuations in ${}^{4}$He.
