Self-consistent solution for proximity effect and Josephson current in ballistic graphene SNS Josephson junctions

Black‐Schaffer, Annica M.; Doniach, Sebastian

doi:10.1103/physrevb.78.024504

Cited by 99 publications

(130 citation statements)

References 21 publications

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“…17 Subsequently, numerous other theoretical works investigated the Josephson current in SGS structures. 14,[18][19][20][21][22][23] The tunneling effect in SG structures has been studied in several works [24][25][26][27][28] as well. Other works in the field of graphene-superconductor heterostructures include studies on crossed Andreev reflection in a graphene bipolar transistor, 29,30 on s-and d-wave SG junctions 31,32 and on ferromagnetic SG structures.…”

Section: Introductionmentioning

confidence: 99%

Josephson current in ballistic superconductor-graphene systems

2010

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We calculate the phase, the temperature and the junction length dependence of the supercurrent for ballistic graphene Josephson junctions. For low temperatures we find nonsinusoidal dependence of the supercurrent on the superconductor phase difference for both short and long junctions. The skewness, which characterizes the deviaton of the current-phase relation from a simple sinusoidal one, shows a linear dependence on the critical current for small currents. We discuss the similarities and differences with respect to the classical theory of Josephson junctions, where the weak link is formed by a diffusive or ballistic metal. The relation to other recent theoretical results on graphene Josephson junctions is pointed out and the possible experimental relevance of our work is considered as well.

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Section: Introductionmentioning

confidence: 99%

Josephson current in ballistic superconductor-graphene systems

2010

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“…Theoretically, it is expected 13,26 that a JJG can carry a non-zero supercurrent even at the CNP, where the charge density is tuned to zero. In this case, the I c R n product is nearly constant as B2D/e with V bg in a ballistic short junction 13 , which is in essence the Ambegaokar-Baratoff relation 14 ; in a diffusive long junction, it is given by aE Th /e (refs 11,27), where E Th is the Thouless energy and a is a coefficient depending on E Th /D.…”

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confidence: 99%

Complete gate control of supercurrent in graphene p–n junctions

et al. 2013

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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.

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“…In contrast to traditional JJ, in which the weak links are insulators, normal metals (N) or constrictions, a superconductor/graphene/superconductor (SGS) JJ consists of a ballistic, 2D relativistic system with gate-tunable conductance [11][12][13][14]. Several unusual phenomena were predicted to arise in this novel system, such as specular Andreev reflection [15], novel propagating modes of Andreev electrons [16] and oscillation of tunneling probability with barrier width [17].…”

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confidence: 99%

Premature switching in graphene Josephson transistors

Miao

Bao

Zhang

et al. 2009

Solid State Communications

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We investigate electronic transport in single layer graphene coupled to superconducting electrodes. In these Josephson transistors, we observe significant suppression in the critical current I c and large variation in the product I c R n in comparison to theoretic predictions in the ballistic limit. We show that the depression of I c can be explained by premature switching in underdamped Josephson junctions described within the resistively and capacitively shunted junction (RCSJ) model. By considering the effect of premature switching and dissipation, the calculated gate dependence of product I c R n agrees with experimental data. Our discovery underscores the crucial role of thermal fluctuations in electronic transport in graphene Josephson transistors.

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Self-consistent solution for proximity effect and Josephson current in ballistic graphene SNS Josephson junctions

Cited by 99 publications

References 21 publications

Josephson current in ballistic superconductor-graphene systems

Josephson current in ballistic superconductor-graphene systems

Complete gate control of supercurrent in graphene p–n junctions

Premature switching in graphene Josephson transistors

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