Probing the superconducting condensate on a nanometer scale

Abstract

Superconductivity is a rare example of a quantum system in which the wavefunction has a macroscopic quantum effect, due to the unique condensate of electron pairs. The amplitude of the wavefunction is directly related to the pair density, but both amplitude and phase enter the Josephson current : the coherent tunneling of pairs between superconductors. Very sensitive devices exploit the superconducting state, however properties of the {\it condensate} on the {\it local scale} are largely unknown, for instance, in unconventional high-T${}_c$ cuprate, multiple gap, and gapless superconductors. The technique of choice would be Josephson STS, based on Scanning Tunneling Spectroscopy (STS), where the condensate is {\it directly} probed by measuring the local Josephson current (JC) between a superconducting tip and sample. However, Josephson STS is an experimental challenge since it requires stable superconducting tips, and tunneling conditions close to atomic contact. We demonstrate how these difficulties can be overcome and present the first spatial mapping of the JC on the nanometer scale. The case of an MgB${}_2$ film, subject to a normal magnetic field, is considered.

7 pages, 6 figures

References in corpus (9)

• Discovery of microscopic electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O8+x
• Two Gap State Density in MgB${}_2$: A True Bulk Property or A Proximity Effect?
• Vortex Imaging in the pi-Band of Magnesium Diboride
• Inherent Inhomogeneities in Tunneling Spectra of BSCCO Crystals in the Superconducting State
• Fluctuation Dominated Josephson Tunneling with a Scanning Tunneling Microscope
• On the use of STM superconducting tips at very low temperatures
• Nanometer Scale Mapping of the Density of States in an Inhomogeneous Superconductor
• Josephson scanning tunneling microscopy
• Fabrication and characterization of scanning tunneling microscopy superconducting Nb tips having highly enhanced critical fields

Cited by in corpus (16)

• Roton pair density wave and unconventional strong-coupling superconductivity in a topological kagome metal
• The Physics of Pair Density Waves
• Detection of a Cooper-Pair Density Wave in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$
• Phase controlled superconducting proximity effect probed by tunneling spectroscopy
• Scanning Josephson spectroscopy on the atomic scale
• Electron tunneling into a quantum wire in the Fabry-Perot regime
• Critical Josephson current in the dynamical Coulomb blockade regime
• Probing Inhomogeneous Cuprate Superconductivity by Terahertz Josephson Echo Spectroscopy
• Sublattice modulated superconductivity in the Kagome Hubbard model
• Single Channel Josephson Effect in a High Transmission Atomic Contact
• Quantum Brownian motion at strong dissipation probed by superconducting tunnel junctions
• calcQPI: A versatile tool to simulate quasiparticle interference
• Plasma etching of superconducting Niobium tips for scanning tunneling microscopy
• The feedback driven atomic scale Josephson microscope
• Correlations Among STM Observables in Disordered Unconventional Superconductors
• Casimir effect in Josephson junctions