论文标题

二维发作同位结构中的声子魔术角

Phonon Magic Angle in Two-Dimensional Puckered Homostructures

论文作者

Zhang, Yufeng, An, Meng, Song, Dongxing, Wang, Haidong, Ma, Weigang, Zhang, Xing

论文摘要

Twistronics的出现提供了一个空前的平台来调节频带结构,从而导致奇特的电子现象从铁磁剂到超导性。但是,仍然缺乏关于声子工程的这种概念。在这里,我们将“ Twistnonics”扩展到2D冰球的材料,并通过分子动力学模拟发现的“声子魔法角”。具有TP-1和TP-2方向重叠的声子魔法角度仍然是高水平,甚至增强了由于范德华(Van der Waals)限制而引起的声子传输能力。这种新颖的现象起源于狭窄的VDW相互作用和由完美的晶格布置引起的有序原子振动,即顶层的原子可以粘在底层的空间上。此外,发现可以通过施加扭曲来有效调节面内和平面外热运输特性。通过语音和电子分析,其他扭曲角度的声子传输能力的恶化归因于抑制声音子模式,降低了声子寿命以及层之间的晶格振动不匹配。我们的发现揭示了低维不对称材料的扭曲杂志,可以进一步扩展到电子和光子设备。

The emergence of twistronics provides an unprecedented platform to modulate the band structure, resulting in exotic electronic phenomena ranging from ferromagnetism to superconductivity. However, such concept on phonon engineering is still lacking. Here, we extend the 'twistnonics' to 2D puckered materials with a 'phonon magic angle' discovered by molecular dynamics simulation. The phonon magic angle, with the TP-1 and TP-2 direction overlapped, remains a high level or even enhances phonon transport capability due to van der Waals confinement. This novel phenomenon originates from the confined vdW interaction and ordered atomic vibration caused by the perfect lattice arrangement that the atoms of the top layer can be stuck to the spaces of the bottom layer. Moreover, it is found that both the in-plane and out-of-plane thermal transport properties can be effectively regulated by applying the twist. Through the phononic and electronic analysis, the deterioration of phonon transport capability for other twist angles are attributed to the suppression of acoustic phonon modes, reduction of phonon lifetimes and mismatched lattice vibration between layers. Our findings shed light on the twistnonics of low-dimensional asymmetrical materials and can be further extended to electronic and photonic devices.

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