Phonon engineering of boron nitride via isotopic enrichment
Phonon engineering of boron nitride via isotopic enrichment
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DOI：
10.1557/s43578-021-00426-9
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发表时间：
2021-11
影响因子：
2.7
通讯作者：
Mingze He;L. Lindsay;T. Beechem;T. Folland;Joseph R Matson;Kenji Watanabe;A. Zavalin;Akira Ueda;W. E. Collins;T. Taniguchi;J. Caldwell
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作者：
Mingze He;L. Lindsay;T. Beechem;T. Folland;Joseph R Matson;Kenji Watanabe;A. Zavalin;Akira Ueda;W. E. Collins;T. Taniguchi;J. Caldwell
声子极化激元（PhP）可以实现各种应用，但它需要在所需频率范围内支持PhP。两种BN同素异形体（立方和六方，cBN和hBN）特别令人感兴趣，因为它们的光学声子落在所谓的分子指纹区域（~ 1000-1610 cm−1）内。然而，这两种PhP之间仍然存在光谱间隙，限制了应用。因此，我们对hBN和cBN进行了同位素工程改造，并检查了光学声子。对于hBN，观察到光学声子寿命和频移的增强。然而，观察到寿命随着cBN被10 B、11B和15 N富集而降低。我们建议，减少的寿命是不是由于固有的损失，而是增加的缺陷浓度所造成的修改后的增长，第一性原理计算的支持。因此，减少同位素工程cBN中的非本征缺陷可能是克服这些限制的分子指纹区域应用的一条途径。
Phonon polaritons (PhPs) enable a variety of applications, yet it requires PhPs supported in the desired frequency range. The two BN allotropes (cubic and hexagonal, cBN and hBN) are of particular interest, as their optic phonons fall within the so-called molecular-fingerprint region (~ 1000–1610 cm−1). However, there remains a spectral gap between PhPs covered by these two, limiting applications. Thus, we isotopically engineered hBN and cBN and examined the optic phonons. For hBN, enhancement of the optic phonon lifetimes and shifted frequencies are observed. However, lifetimes are observed to decrease with the enrichment of cBN by 10B, 11B, and 15N. We propose that the reduced lifetimes are not due to intrinsic loss, but rather increased defect concentrations resulting from the modified growth, supported by first-principles calculations. Thus, reducing the extrinsic defects in isotopically engineered cBN may present a path toward overcoming these restrictions for applications in the molecular-fingerprint region.