Controlling Three Laser-Excited Coherent Phonon Modes in Boron Nitride Nanotubes To Produce Ultrashort Shaped Terahertz Pulses: Implications for Memory Devices
Controlling Three Laser-Excited Coherent Phonon Modes in Boron Nitride Nanotubes To Produce Ultrashort Shaped Terahertz Pulses: Implications for Memory Devices
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DOI：
10.1021/acsanm.8b01716
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发表时间：
2018-11
影响因子：
5.9
通讯作者：
B. Bauerhenne;E. S. Zijlstra;A. Kalitsov;Martin E. Garcia
中科院分区：
文献类型：
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作者：
B. Bauerhenne;E. S. Zijlstra;A. Kalitsov;Martin E. Garcia
超快激光脉冲对晶格振动的激发提供了一种工具来引导原子尺度的运动，使其超越通常的热力学限制。我们在扶手椅、手性和锯齿形氮化硼纳米管(BNNTs)中模拟了这一过程。特别是，对于超薄的锯齿形管子，我们证明了三个振动模可以被位移激发。由于氮化硼的键是极性的，三个相干声子振荡发射太赫兹(THz)辐射。本文以最薄、最稳定的(5，0)锯齿形BNNT为研究对象，通过从头算分子动力学模拟和优化算法，证明了激光脉冲串可以控制三个声子模的相对幅度以及相应的太赫兹短脉冲的形状。我们的工作可以为利用BNNTs的相干振动作为纳米声子学中的光存储器件的实验研究提供基础，因为信息可以通过几个F写入声子系统。
The excitation of lattice vibrations by ultrafast laser pulses provides a tool to steer atomic-scale motions beyond usual thermodynamic limitations. We simulate this process in armchair, chiral, and zigzag boron nitride nanotubes (BNNTs). In particular, for ultrathin zigzag-type tubes we show that three vibrational modes can be displacively excited. Since the boron nitride bonds are polar, the three coherent phonon oscillations emit terahertz (THz) radiation. In this work we focus on the (5,0) zigzag BNNT, which is the thinnest stable one, and demonstrate, by means of ab initio molecular dynamics simulations and optimization algorithms, that the relative amplitudes of the three phonon modes and therefore the corresponding shape of the emitted THz short pulse can be controlled by laser-pulse trains. Our work could serve as a basis for experimental studies using the coherent vibrations of BNNTs as optical memory devices in nanophononics, since information could be written in the phononic system by several f...