Microwave photon-assisted phase-incoherent Cooper-pair tunneling in a Josephson STM
arXiv:1510.06440 · doi:10.1103/PhysRevApplied.4.034011
Abstract
We have observed photon-assisted Cooper-pair tunneling in an atomic-scale Josephson junction formed between a superconducting Nb tip and a superconducting Nb sample in a scanning tunneling microscope (STM) at 30 mK. High-resolution tunneling spectroscopy data show a zero-bias conduction peak and other sharp sub-gap peaks from coupling of the STM junction to resonances in the electromagnetic environment. The sub-gap peaks respond to incident microwave radiation by splitting into multiple peaks with the position and height depending on the frequency and amplitude of the microwaves. The inter-peak spacing shows that the charge carriers are Cooper pairs, rather than quasiparticles, and the power dependence reveals that the current originates from photon-assisted phase-incoherent tunneling of pairs, rather than the more conventional phase-coherent tunneling of pairs that yields Shapiro steps.
7 pages, 8 figures
References in corpus (7)
- Scanning tunneling spectroscopy of high-temperature superconductors
- Colloquium: Majorana Fermions in nuclear, particle and solid-state physics
- Bulk and Surface Tunneling Hydrogen Defects in Alumina
- Scanning tunneling spectroscopy with superconducting tips of Al
- A 30 mK, 13.5 T scanning tunneling microscope with two independent tips
- Dynamic parity recovery in a strongly driven Cooper-pair box
- Plasma etching of superconducting Niobium tips for scanning tunneling microscopy
Cited by in corpus (18)
- Diode effect in Josephson junctions with a single magnetic atom
- Quantized current steps due to the a.c. coherent quantum phase-slip effect
- Scanning Josephson spectroscopy on the atomic scale
- Single-atom electron paramagnetic resonance in a scanning tunneling microscope driven by a radiofrequency antenna at 4 K
- Microwave-assisted tunneling and interference effects in superconducting junctions under fast driving signals
- Photon-assisted tunneling at the atomic scale: Probing resonant Andreev reflections from Yu-Shiba-Rusinov states
- Electric Control of Spin Transitions at the Atomic Scale
- Photon-assisted resonant Andreev reflections: Yu-Shiba-Rusinov and Majorana states
- Combining Electron Spin Resonance Spectroscopy with Scanning Tunneling Microscopy at High Magnetic Fields
- A millikelvin scanning tunneling microscope in ultra-high vacuum with adiabatic demagnetization refrigeration
- Quantifying quantum coherence of multiple-charge states in tunable Josephson junctions
- Single Channel Josephson Effect in a High Transmission Atomic Contact
- Microscopic theory of photo-assisted electronic transport in normal-metal/BCS-superconductor junctions
- Microwave-induced conductance replicas in hybrid Josephson junctions without Floquet-Andreev states
- Photon assisted tunneling of high order multiple Andreev reflections in epitaxial nanowire Josephson junctions
- Microwave Excitation of Atomic Scale Superconducting Bound States
- A particle conserving approach to AC-DC driven interacting quantum dots with superconducting leads
- Direct observation of intrinsic surface magnetic disorder in amorphous superconducting films