title: Electromagnetic Saturation of Angstrom-Sized Quantum Barriers at Terahertz Frequencies.
abstract: Metal-graphene-metal hybrid structures allow angstrom-scale van der Waals gaps, across which electron tunneling occurs. We squeeze terahertz electromagnetic waves through these λ/10 000 000 gaps, accompanied by giant field enhancements. Unprecedented transmission reduction of 97% is achieved with the transient voltage across the gap saturating at 5 V. Electron tunneling facilitated by the transient electric field strongly modifies the gap index, starting a self-limiting process related to the barrier height. Our work enables greater interplay between classical optics and quantum tunneling, and provides optical indices to the van der Waals gaps.
authors.affiliation: Department of Physics and Astronomy and Center for Atomic Scale Electromagnetism, Seoul National University, Seoul 151-747, Korea.
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Bahk
authors.affiliation: Department of Energy Systems Research and Department of Physics, Ajou University, Suwon 443-749, Korea.
authors.forename: Bong Joo
authors.initials: BJ
authors.lastname: Kang
authors.affiliation: Graphene Research Institute and Department of Physics, Sejong University, Seoul 143-747, Korea.
authors.forename: Yong Seung
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Physics and Astronomy and Center for Atomic Scale Electromagnetism, Seoul National University, Seoul 151-747, Korea.
authors.forename: Joon-Yeon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Energy Systems Research and Department of Physics, Ajou University, Suwon 443-749, Korea.
authors.forename: Won Tae
authors.initials: WT
authors.lastname: Kim
authors.affiliation: Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747, Korea.
authors.forename: Tae Yun
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Department of Physics and Astronomy and Center for Atomic Scale Electromagnetism, Seoul National University, Seoul 151-747, Korea.
authors.forename: Taehee
authors.initials: T
authors.lastname: Kang
authors.affiliation: Department of Physics and Astronomy and Center for Atomic Scale Electromagnetism, Seoul National University, Seoul 151-747, Korea.
authors.forename: Jiyeah
authors.initials: J
authors.lastname: Rhie
authors.affiliation: Photonic Systems Laboratory, School of EECS, Seoul National University, Seoul 151-744, Korea.
authors.forename: Sanghoon
authors.initials: S
authors.lastname: Han
authors.affiliation: Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747, Korea.
authors.forename: Cheol-Hwan
authors.initials: CH
authors.lastname: Park
authors.affiliation: Department of Energy Systems Research and Department of Physics, Ajou University, Suwon 443-749, Korea.
authors.forename: Fabian
authors.initials: F
authors.lastname: Rotermund
authors.affiliation: Department of Physics and Astronomy and Center for Atomic Scale Electromagnetism, Seoul National University, Seoul 151-747, Korea.
authors.forename: Dai-Sik
authors.initials: DS
authors.lastname: Kim