A nanoscale gigahertz source realized with Josephson scanning tunneling microscopy
- Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart (Germany)
- Institut für Theoretische Elektrotechnik, Technische Universität Hamburg-Harburg, 21079 Hamburg (Germany)
Using the AC Josephson effect in the superconductor-vacuum-superconductor tunnel junction of a scanning tunneling microscope (STM), we demonstrate the generation of GHz radiation. With the macroscopic STM tip acting as a λ/4-monopole antenna, we first show that the atomic scale Josephson junction in the STM is sensitive to its frequency-dependent environmental impedance in the GHz regime. Further, enhancing Cooper pair tunneling via excitations of the tip eigenmodes, we are able to generate high-frequency radiation. We find that for vanadium junctions, the enhanced photon emission can be tuned from about 25 GHz to 200 GHz and that large photon flux in excess of 10{sup 20 }cm{sup −2} s{sup −1} is reached in the tunnel junction. These findings demonstrate that the atomic scale Josephson junction in an STM can be employed as a full spectroscopic tool for GHz frequencies on the atomic scale.
- OSTI ID:
- 22395670
- Journal Information:
- Applied Physics Letters, Vol. 106, Issue 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTENNAS
COOPER PAIRS
ELECTRIC CONTACTS
EXCITATION
FREQUENCY DEPENDENCE
GHZ RANGE
IMPEDANCE
JOSEPHSON EFFECT
JOSEPHSON JUNCTIONS
NANOSTRUCTURES
PHOTON EMISSION
PHOTONS
SCANNING TUNNELING MICROSCOPY
SHORT WAVE RADIATION
SUPERCONDUCTORS
TUNNEL EFFECT
VANADIUM