Loss mechanisms in superconducting thin film microwave resonators
Loss mechanisms in superconducting thin film microwave resonators
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DOI：
10.1063/1.4939299
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发表时间：
2016-01-07
影响因子：
3.2
通讯作者：
Gross, Rudolf
中科院分区：
文献类型：
--
作者：
Goetz, Jan;Deppe, Frank;Gross, Rudolf
本文系统地分析了硅基铌薄膜超导共面波导微波谐振器的内部损耗。特别是，我们调查的Nb/A1接口的中心导体，这是很重要的实验中，A1为基础的约瑟夫森结集成到Nb为基础的电路中引入的损失。我们发现，这些接口可以是一个强大的源两级状态（TLS）的损失，当接口不位于当前节点的谐振器。除了TLS损耗之外，对于包括A1的谐振器，准粒子损耗在200 mK以上变得相关。最后，我们研究如何通过使用足够厚的基板或基板背面上具有高导电性的金属来最小化基板背面上的导电材料中的涡电流所产生的损耗。(c)2016 AIP Publishing LLC.
We present a systematic analysis of the internal losses of superconducting coplanar waveguide microwave resonators based on niobium thin films on silicon substrates. In particular, we investigate losses introduced by Nb/A1 interfaces in the center conductor, which is important for experiments where A1 based Josephson junctions are integrated into Nb based circuits. We find that these interfaces can be a strong source for two-level state (TLS) losses, when the interfaces are not positioned at current nodes of the resonator. In addition to TLS losses, for resonators including A1, quasiparticle losses become relevant above 200 mK. Finally, we investigate how losses generated by eddy currents in conductive material on the backside of the substrate can be minimized by using thick enough substrates or metals with high conductivity on the substrate backside. (c) 2016 AIP Publishing LLC.