Josephson Radiation from Gapless Andreev Bound States in HgTe-Based Topological Junctions
Josephson Radiation from Gapless Andreev Bound States in HgTe-Based Topological Junctions
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DOI：
10.1103/physrevx.7.021011
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发表时间：
2017-04-20
影响因子：
12.5
通讯作者：
Molenkamp, L. W.
中科院分区：
文献类型：
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作者：
Deacon, R. S.;Wiedenmann, J.;Molenkamp, L. W.
振荡约瑟夫森超流射频发射的频谱分析是探索约瑟夫森结拓扑特性的有力被动手段。特别是，约瑟夫森发射的测量使得能够检测到在约瑟夫森频率f(J)的一半处产生发射而不是在f(J)处产生常规发射的拓扑无间隙Andreev束缚态。在这里，我们报道了直接测量由基于HgTe的栅调谐拓扑弱链构成的约瑟夫森结的射频发射光谱。发射光谱在约瑟夫森频率f(J)/2的一半处显示出清晰的信号。发射线的线宽表明，f(J)/2谱线的相干时间为0.3-4 ns，远短于f(J)谱线(3-4 ns)。这些观察结果有力地指出了拓扑无间隙Andreev束缚态的存在，并为未来基于HgTe的拓扑量子计算平台铺平了道路。
Frequency analysis of the rf emission of oscillating Josephson supercurrent is a powerful passive way of probing properties of topological Josephson junctions. In particular, measurements of the Josephson emission enable the detection of topological gapless Andreev bound states that give rise to emission at half the Josephson frequency f(J) rather than conventional emission at f(J). Here, we report direct measurement of rf emission spectra on Josephson junctions made of HgTe-based gate-tunable topological weak links. The emission spectra exhibit a clear signal at half the Josephson frequency f(J)/2. The linewidths of emission lines indicate a coherence time of 0.3-4 ns for the f(J)/2 line, much shorter than for the f(J) line (3-4 ns). These observations strongly point towards the presence of topological gapless Andreev bound states and pave the way for a future HgTe-based platform for topological quantum computation.