Recent experiments and simulations are starting to answer some fundamental questions about how life came to be.
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Edited by Eduardo Fradkin, University of Illinois at Urbana–Champaign, Urbana, IL, and approved May 21, 2018 (received for review January 2, 2018)
Article Figures & SI
Figures
- Fig. 1.
Nondissipative current at 2- and 3TJs. (A) Schematic illustration of a two-terminal Josephson junction. (B) Schematic illustration of a 3TJ with a narrow central contact, and the formation of a quartet by combining two distinct Cooper pairs. (C) Schematic illustration of the two-terminal resonance process of an ABS, enabling Josephson supercurrent flow. (D) Schematic illustration of the three-terminal quartet ABS, leading to a nonlocal supercurrent flow. (E) Dependence of the two quartet particle–hole conjugates ABSs on the phase
- Fig. 2.
Devices and differential conductance results. (A) SEM image of device d1. (Scale bar, 300 nm.) The central superconducting contact is 200 nm, namely, on the same order of magnitude as the coherence length. The gates (in green) were used to tune the transmission of the junction. (B) SEM image of device d2. (Scale bar is of length 300 nm.) The central superconducting contact is 3 µm wide, much larger than the coherence length. (C) GL as a function of VL and VR measured in device d1. The quartet line, as well as other expected diagonal lines, is clearly seen. The solid line and dashed square are guidelines to Fig. 4A, Top and Fig. 4B. (D) GL as function of VL and VR measured in device d2. No vertical or diagonal lines are observed. (E) GL (blue) and GR (red) as a function of VL in d1. The shape of the quartet peak, which resembles the Josephson current with the two side dips, is shown in the upper right corner with the quartet energy.
- Fig. 3.
Differential conductance correlation measurements between the right and left terminals. (A and B) GL and GR, respectively, as a function of the left contact bias VL, and the right gate voltage VGR, while VR = 15 µV.
- Fig. 4.
CC of current fluctuations and nonlocal conductance measurements. (A, Upper) Differential conductance cuts of GL and GR along the solid line in Fig. 2C. (A, Lower) CC of current fluctuations at the left and right terminals. (B) CC as a function of VL and VR in the region defined by the dashed square of Fig. 2C. (C, Upper) CC along the quartet line. (C, Lower) Theoretical calculation of the CC (SI Appendix). The maxima are due to Landau–Zener resonances. (Inset) Zoom-out in the bias voltage range. It should be noted that the measured CC also drops beyond 20 µV.
Data supplements
Supporting Information
Nonlocal supercurrent of quartets in a three-terminal Josephson junction
Article Classifications
- Physical Sciences
- Physics
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