Research Status
Atomic-scale Visualization of Electronic Fluid Flow
Nature Materials 20, 1480(2021)
Essence: Direct atomic-scale imaging of flowing electrons has long eluded physicists. To do so, we introduced a technique based on superconductive-tip STM and the Galilean energy boost to quasiparticles due to the flowing electron-pair condensate. We demonstrated how to visualize electronic fluid flow for speeds between 100m/s and 3500 m/s around an Abrikosov vortex. Fundamentally, this approach to imaging flowing electronic fluids is generalizable universally.
Top row and bottom left: Schematic of splitting the quasiparticle coherence peaks in the density of states of a superconductor by an energy 2kFVs , where kF is Fermi wavevector and Vs is the speed with which the electron-pair fluid is moving relative to the scan tip. Bottom center: Atomic resolution image of flowing supercurrent speeds ranging from 100m/S to 3500 m/s.
We used superconducting-tip scanning tunnelling microscopy to image the electron-pair density and velocity fields of the flowing electron-pair fluid in superconducting NbSe2. Imaging of the velocity fields surrounding a quantized vortex finds electronic fluid flow with speeds reaching 10,000 km h-1. Together with independent imaging of the electron-pair density via SJTM, we visualize the supercurrent density, which peaks above 3 107 A cm-2. The spatial patterns in electronic fluid flow and magneto-hydrodynamics reveal hexagonal structures coaligned to the crystal lattice and quasiparticle bound states as long anticipated. These techniques pave the way for atomic-scale electronic fluid flow visualization studies of other charged quantum fluids.
Macroscopic Quantum Matter
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