Experimental study of ac Josephson effect in gate-tunable (Bi1−xSbx)2Te3 thin-film Josephson junctions
Experimental study of ac Josephson effect in gate-tunable (Bi1−xSbx)2Te3 thin-film Josephson junctions
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DOI：
10.1103/physrevb.101.115410
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发表时间：
2020-03
影响因子：
3.7
通讯作者：
Yuusuke Takeshige;S. Matsuo;R. Deacon;K. Ueda;Yosuke Sato;Yi-Fan Zhao;Lingjie Zhou;Cui-Zu Chang;K. Ishibashi;S. Tarucha
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文献类型：
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作者：
Yuusuke Takeshige;S. Matsuo;R. Deacon;K. Ueda;Yosuke Sato;Yi-Fan Zhao;Lingjie Zhou;Cui-Zu Chang;K. Ishibashi;S. Tarucha
本文报道了利用背栅费米能量调谐技术测量三维拓扑绝缘体约瑟夫森结的交流约瑟夫森效应。我们成功地将费米能调谐到TI的体能隙中。我们观察到，作为门电压的函数的约瑟夫森能量有一个下降的功能，表明镜面Andreev反射的存在。我们研究了交流约瑟夫森效应的夏皮罗台阶和约瑟夫森发射的检测。得到的结果表明没有签名的马约拉纳模式。在模拟的支持下，我们得出结论，分数交流约瑟夫森效应的观察可能是复杂的，由一个大的并联电容和一个小比例的电流进行周期模式相比，conventialmodes。
We report on measurements of the ac Josephson effect in three-dimensional topological insulator (TI) Josephson junctions with Fermi energy tuning using a back gate. We successfully tune the Fermi energy into the bulk gap of the TI. We observe that the Josephson energy as a function of the gate voltage has a dip feature, indicating the presence of specular Andreev reflections. We study the ac Josephson effect with detection of both Shapiro steps and Josephson emission. The obtained results show no signature of Majorana modes. With the support of simulations, we conclude that the observation of the fractional ac Josephson effect may be complicated by both a large parallel capacitance and a small ratio of current carried inperiod modes compared to conventionalmodes.