We report measurements of the current-phase relation of two voltage-controlled semiconductor-superconductor hybrid Josephson junctions (JJs) in series. The two hybrid junctions behave similar to a single-mode JJ with effective transparency determined by the ratio of Josephson coupling strengths of the two junctions. Gate-voltage control of Josephson coupling (measured from switching currents) allows tuning of the harmonic content from sinusoidal, for asymmetric tuning, to highly nonsinusoidal, for symmetric tuning. The experimentally observed tunable harmonic content agrees with a model based on two conventional (sinusoidal) JJs in series.

中文翻译：

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混合 Josephson 结电路中高次谐波的电压控制合成


我们报告了两个串联的压控半导体-超导体混合约瑟夫森结 （JJ） 的电流-相位关系的测量结果。两个混合结的行为类似于单模 JJ，其有效透明度由两个结的 Josephson 耦合强度之比决定。Josephson 耦合的栅极电压控制（通过开关电流测量）允许将谐波含量从正弦（用于非对称调谐）调谐到高度非正弦（用于对称调谐）。实验观察到的可调谐波含量与基于两个串联的常规（正弦）JJ 的模型一致。