Origin of mechanical and dielectric losses from two-level systems in amorphous silicon
Origin of mechanical and dielectric losses from two-level systems in amorphous silicon
复制标题
非晶硅两能级系统机械和介电损耗的起源
DOI：
10.1103/physrevmaterials.5.035601
复制
发表时间：
2021
影响因子：
3.4
通讯作者：
Hellman, F.
中科院分区：
文献类型：
--
作者：
Molina-Ruiz, M.;Rosen, Y. J.;Jacks, H. C.;Abernathy, M. R.;Metcalf, T. H.;Liu, X.;DuBois, J. L.;Hellman, F.
非晶硅包含隧穿二能级系统，这是低温下非晶固体的主要能量损失机制。这些两能级系统影响机械和电磁振荡器，并且被认为产生热和电磁噪声以及能量损失。然而，目前还不清楚主导机械和介电损耗的两能级系统是否相同;前者依赖于声子和两能级系统之间的耦合，具有弹性场耦合常数，而后者依赖于两能级系统的偶极矩，它耦合到电磁场。机械和介电损耗的测量以及结构表征进行电子束沉积生长的非晶硅薄膜的生长参数范围。与室温下生长的样品相比，在425 ℃下生长的样品显示出机械损耗的大幅度降低（34倍）和介电损耗的小得多的降低（2.3倍）。此外，机械损耗显示较厚的膜的较低的损耗，而介电损耗显示较薄的膜的较低的损耗。对这些结果的分析表明，机械损耗与原子密度相关，而介电损耗与悬挂键密度相关，这表明非晶硅中这两种能量耗散过程的起源不同。
Amorphous silicon contains tunneling two-level systems, which are the dominant energy loss mechanisms for amorphous solids at low temperatures. These two-level systems affect both mechanical and electromagnetic oscillators and are believed to produce thermal and electromagnetic noise and energy loss. However, it is unclear whether the two-level systems that dominate mechanical and dielectric losses are the same; the former relies on the coupling between phonons and two-level systems, with an elastic field coupling constantwhile the latter depends on a two-level systems dipole moment, which couples to the electromagnetic field. Mechanical and dielectric loss measurements as well as structural characterization were performed on amorphous silicon thin films grown by electron beam deposition with a range of growth parameters. Samples grown at 425show a large reduction of mechanical loss (34 times) and a far smaller reduction of dielectric loss (2.3 times) compared to those grown at room temperature. Additionally, mechanical loss shows lower loss for thicker films, while dielectric loss shows lower loss for thinner films. Analysis of these results indicate that mechanical loss correlates with atomic density, while dielectric loss correlates with dangling-bond density, suggesting a different origin for these two energy dissipation processes in amorphous silicon.
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DOI：
10.1007/s002570050205
发表时间：
1996-10-01
期刊：
ZEITSCHRIFT FUR PHYSIK B-CONDENSED MATTER
影响因子：
--
作者：
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通讯作者：
Cahill, DG
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DOI：
10.1103/physrevb.52.7179
发表时间：
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期刊：
Physical review. B, Condensed matter
影响因子：
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影响因子：
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发表时间：
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期刊：
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影响因子：
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影响因子：
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