Bipolar supercurrent in graphene

By H. Heersche, P. Jarillo-Herrero, J. Oostinga, Lieven M. K. Vandersypen, A. Morpurgo. Nature, 2006

1,026 citations recorded by the source corpus.

Graphene—a recently discovered form of graphite only one atomic layer thick—constitutes a new model system in condensed matter physics, because it is the first material in which charge carriers behave as massless chiral relativistic particles. The anomalous quantization of the Hall conductance, which is now understood theoretically, is one of the experimental signatures of the peculiar transport properties of relativistic electrons in graphene. Other unusual phenomena, like the finite conductivity of order 4e2/h (where e is the electron charge and h is Planck’s constant) at the charge neutrality (or Dirac) point, have come as a surprise and remain to be explained. Here we experimentally study the Josephson effect in mesoscopic junctions consisting of a graphene layer contacted by two closely spaced superconducting electrodes. The charge density in the graphene layer can be controlled by means of a gate electrode. We observe a supercurrent that, depending on the gate voltage, is carried by either electrons in the conduction band or by holes in the valence band. More importantly, we find that not only the normal state conductance of graphene is finite, but also a finite supercurrent can flow at zero charge density. Our observations shed light on the special role of time reversal symmetry in graphene, and demonstrate phase coherent electronic transport at the Dirac point.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/ed8d8308ea97301f80f2f20ca8d797f582cb71b2

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. E. Rossi
2. J. Alicea
3. E. Hwang
4. S. Adam
5. N. Lindner
6. A. Stern
7. C. Nayak
8. P. Fendley

In Materials Chemistry

1. E. Rossi
2. Zhenhua Ni
3. T. Yu
4. E. Hwang
5. S. Adam
6. Zexiang Shen
7. Yingying Wang
8. Xiaoping Shen

Citations in the corpus

• Electronic transport in two-dimensional graphene (2010, background): “Graphene can also be made to superconduct by coupling it to superconducting leads and through the proximity effect (Beenakker, 2006, 2008; Du et al., 2008a; Heersche et al., 2007) or other novel proposals (Feigel’man et al., 2008; Lutchyn et al., 2008).”
• The role of contact resistance in graphene field-effect devices (2017, neutral): “T i T it an iu m Ti/Al (10/70) E-Beam Exfoliated 2p/4p <250 [138] Ti/Au (10/20) Th.”
• Phase-Coherent Transport in Graphene Quantum Billiards (2007, background): “We note that even though enhanced conductance due to proximity effect is observed, we did not observe supercurrent through the devices (although in a very recent report supercurrent through graphene was reported [41]).”
• Growth of graphene on Ir(111) (2009, background): “Other fundamental questions come along with the metal/graphene interface, in particular, considering supercurrent with Dirac-like electrons flowing between two metallic electrodes coupled through a graphene layer to a superconductor [20].”