Localization of Metal-Induced Gap States at the Metal-Insulator Interface: Origin of Flux Noise in SQUIDs and Superconducting Qubits
Localization of Metal-Induced Gap States at the Metal-Insulator Interface: Origin of Flux Noise in SQUIDs and Superconducting Qubits
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DOI：
10.1103/physrevlett.103.197001
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发表时间：
2009-11-06
影响因子：
8.6
通讯作者：
Clarke, John
中科院分区：
文献类型：
--
作者：
Choi, SangKook;Lee, Dung-Hai;Clarke, John
功率谱尺度为1/f(f为频率)的超导量子干涉器件的磁通噪声的来源一直是20多年来的一个谜。这种噪声限制了超导量子比特的消相干时间。一种共识是，噪声是由面密度为5x10(17)m(-2)的局域电子的起伏自旋引起的。我们发现，在金属-绝缘体界面处存在势无序时，一些金属诱导的带隙状态会局域化并产生局域矩。适度的无序会产生观察到的面密度。
The origin of magnetic flux noise in superconducting quantum interference devices with a power spectrum scaling as 1/f (f is frequency) has been a puzzle for over 20 years. This noise limits the decoherence time of superconducting qubits. A consensus has emerged that the noise arises from fluctuating spins of localized electrons with an areal density of 5x10(17) m(-2). We show that, in the presence of potential disorder at the metal-insulator interface, some of the metal-induced gap states become localized and produce local moments. A modest level of disorder yields the observed areal density.