Time-reversal-invariant Z4 fractional Josephson effect.
Time-reversal-invariant Z4 fractional Josephson effect.
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DOI：
10.1103/physrevlett.113.036401
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发表时间：
2014-04
影响因子：
8.6
通讯作者：
Fan Zhang;C. L. Kane
中科院分区：
文献类型：
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作者：
Fan Zhang;C. L. Kane
我们研究了量子自旋霍尔边缘态介导的约瑟夫森结，并表明，电子-电子相互作用导致无耗散的分数约瑟夫森效应的存在下的时间反转对称性。令人惊讶的是，周期是8π，对应于约瑟夫森频率eV/2 π。我们估计的相互作用引起的多体能级分裂负责这种效果的大小，并认为它可以通过使用隧道光谱测量。对于强相互作用，我们表明约瑟夫森效应与超导体之间的电荷e/2准粒子的弱隧穿有关。我们的理论描述了一个四重的基态简并，这是类似于耦合的“分数”马约拉纳模式，但保护的时间反演对称性。
We study the Josephson junction mediated by the quantum spin Hall edge states and show that electron-electron interactions lead to a dissipationless fractional Josephson effect in the presence of time-reversal symmetry. Surprisingly, the periodicity is 8π, corresponding to a Josephson frequency eV/2ℏ. We estimate the magnitude of interaction-induced many-body level splitting responsible for this effect and argue that it can be measured by using tunneling spectroscopy. For strong interactions we show that the Josephson effect is associated with the weak tunneling of charge e/2 quasiparticles between the superconductors. Our theory describes a fourfold ground state degeneracy that is similar to that of coupled "fractional" Majorana modes but is protected by time-reversal symmetry.