Complete gate control of supercurrent in graphene p-n junctions.
In a conventional Josephson junction of graphene, the supercurrent is not turned off even at the charge neutrality point, impeding further development of superconducting quantum information devices based on graphene. Here we fabricate bipolar Josephson junctions of graphene, in which a p-n potential barrier is formed in graphene with two closely spaced superconducting contacts, and realize supercurrent ON/OFF states using electrostatic gating only. The bipolar Josephson junctions of graphene also show fully gate-driven macroscopic quantum tunnelling behaviour of Josephson phase particles in a potential well, where the confinement energy is gate tuneable. We suggest that the supercurrent OFF state is mainly caused by a supercurrent dephasing mechanism due to a random pseudomagnetic field generated by ripples in graphene, in sharp contrast to other nanohybrid Josephson junctions. Our study may pave the way for the development of new gate-tuneable superconducting quantum information devices.
1] Department of Physics, Pohang University of Science and Technology, Pohang 790 784, Republic of Korea [2].
Jae-Hyun
JH
Choi
Gil-Ho
GH
Lee
Sunghun
S
Park
Dongchan
D
Jeong
Jeong-O
JO
Lee
H-S
HS
Sim
Yong-Joo
YJ
Doh
Hu-Jong
HJ
Lee