title: Quantized edge modes in atomic-scale point contacts in graphene.
abstract: The zigzag edges of single- or few-layer graphene are perfect one-dimensional conductors owing to a set of gapless states that are topologically protected against backscattering. Direct experimental evidence of these states has been limited so far to their local thermodynamic and magnetic properties, determined by the competing effects of edge topology and electron-electron interaction. However, experimental signatures of edge-bound electrical conduction have remained elusive, primarily due to the lack of graphitic nanostructures with low structural and/or chemical edge disorder. Here, we report the experimental detection of edge-mode electrical transport in suspended atomic-scale constrictions of single and multilayer graphene created during nanomechanical exfoliation of highly oriented pyrolytic graphite. The edge-mode transport leads to the observed quantization of conductance close to multiples of G0= 2e2/h. At the same time, conductance plateaux at G0/2 and a split zero-bias anomaly in non-equilibrium transport suggest conduction via spin-polarized states in the presence of an electron-electron interaction.
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: Amogh
authors.initials: A
authors.lastname: Kinikar
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: T
authors.initials: T
authors.lastname: Phanindra Sai
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: Semonti
authors.initials: S
authors.lastname: Bhattacharyya
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: Adhip
authors.initials: A
authors.lastname: Agarwala
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: Tathagata
authors.initials: T
authors.lastname: Biswas
authors.affiliation: Department of Physics, The University of Alabama, Tuscaloosa, Alabama 35487, USA.
authors.forename: Sanjoy K
authors.initials: SK
authors.lastname: Sarker
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: H R
authors.initials: HR
authors.lastname: Krishnamurthy
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Jain
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.
authors.forename: Vijay B
authors.initials: VB
authors.lastname: Shenoy
authors.affiliation: Department of Physics, Indian Institute of Science, Bengaluru 560 012, India.|Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Arindam
authors.initials: A
authors.lastname: Ghosh