Davydova Margarita, Prembabu Saranesh, Fu Liang
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Sci Adv. 2022 Jun 10;8(23):eabo0309. doi: 10.1126/sciadv.abo0309. Epub 2022 Jun 8.
We propose a universal mechanism for the Josephson diode effect in short Josephson junctions. The proposed mechanism is due to finite Cooper pair momentum and is a manifestation of simultaneous breaking of inversion and time-reversal symmetries. The diode efficiency is up to 40%, which corresponds to an asymmetry between the critical currents in opposite directions / ≈ 230%. We show that this arises from both the Doppler shift of the Andreev bound state energies and the phase-independent asymmetric current from the continuum. Last, we propose a simple scheme for achieving finite-momentum pairing, which does not rely on spin-orbit coupling and thus greatly expands existing platforms for the observation of supercurrent diode effects.
我们提出了一种适用于短约瑟夫森结中约瑟夫森二极管效应的通用机制。所提出的机制源于有限的库珀对动量，是反演对称性和时间反演对称性同时破缺的一种表现。二极管效率高达40%，这对应于相反方向临界电流之间的不对称性/≈230%。我们表明，这是由安德列夫束缚态能量的多普勒频移和来自连续体的与相位无关的不对称电流共同引起的。最后，我们提出了一种实现有限动量配对的简单方案，该方案不依赖于自旋轨道耦合，从而极大地扩展了用于观测超流二极管效应的现有平台。
