论文标题
量子异常和异常的约瑟夫森效应在反转的非对称Weyl半法中
Quantum anomaly and anomalous Josephson effect in inversion asymmetric Weyl semimetals
论文作者
论文摘要
我们研究了涉及时间反转对称（TRS）或韦尔光谱中时间反转对称性斜线的约瑟夫森连接，涉及倒置 - 相对的Weyl半准。我们揭示了Weyl节点中的两种类型的倾斜导致Josephson $ 0 $ - $π$过渡和零偏见谷/手性超电流。令人惊讶的是，TRS倾斜产生了纯谷Josephson电流（VJC），而TRS损坏的倾斜度会在此系统中诱导纯手性约瑟夫森电流（CJC）。 vjc和cjc是山谷对称性的表现，$ \ mathbb {z} _2 _2 $由相应的倾斜破裂。即使在连接长度可控制的零偏置条件下，我们也获得了纯VJC和纯CJC的逆转。我们对反转非对称Weyl半分布中山谷和手性依赖性转运的可控性的分析可以分别允许在valleytronics和chiralitytronics中应用。倾斜诱导的约瑟夫森效应为超电流$ 0 $ - $π$过渡提供了另一种途径，与传统的铁磁性约瑟夫森连接不同，旋转极化是必不可少的。在长连接和零温度限制中，VJC和CJC与量子异常相关联，该量子异常在电流中通过不连续的跳跃而表现出的量子异常，分别没有TRS和TRS破裂倾斜。
We study a Josephson junction involving an inversion-asymmetric Weyl semimetal in presence of time-reversal symmetric (TRS) or time-reversal symmetry broken tilt in the Weyl spectra. We reveal that both types of tilts in the Weyl nodes lead to a Josephson $0$-$π$ transition and a zero bias valley/chiral supercurrent. Strikingly, the TRS tilt gives rise to a pure valley Josephson current (VJC) and TRS broken tilt induces a pure chirality Josephson current (CJC) in this system. The VJC and CJC are the manifestation of valley symmetry broken and $\mathbb{Z}_2$ symmetry broken by the respective tilt. We obtain the reversal of a pure VJC and pure CJC even in the zero bias condition controllable by the junction length. Our analysis of controllability of valley and chirality dependent transport in an inversion asymmetric Weyl semimetal junction could allow applications in valleytronics and chiralitytronics, respectively. The tilt induced Josephson effect provides an alternative route for supercurrent $0$-$π$ transition, different from the conventional ferromagnetism Josephson junctions where the spin polarization is essential. In the long junction and zero temperature limit, VJC and CJC are associated with a quantum anomaly which is manifested through a discontinuous jump in the current in absence of TRS and TRS breaking tilts, respectively.
