A5077784395- Quantum and electron transport phenomena
- Near-Field Optical Microscopy
- Physics of Superconductivity and Magnetism
- Surface and Thin Film Phenomena
- Photonic and Optical Devices
- Semiconductor Quantum Structures and Devices
- Superconducting and THz Device Technology
- Mechanical and Optical Resonators
- Quantum Dots Synthesis And Properties
- Particle accelerators and beam dynamics
- Chalcogenide Semiconductor Thin Films
- Perovskite Materials and Applications
- Semiconductor materials and interfaces
- Topological Materials and Phenomena
- Terahertz technology and applications
- Quantum Information and Cryptography
Iowa State University
2022-2025
Ames National Laboratory
2022-2024
We have developed a versatile near-field microscopy platform that can operate at high magnetic fields and below liquid-helium temperatures. use this to demonstrate an extreme terahertz (THz) nanoscope operation obtain the first cryogenic magneto-THz time-domain nano-spectroscopy/imaging temperatures as low 1.8 K, of up 5 T, with 0-2 THz. Our Cryogenic Magneto-Terahertz Scattering-type Scanning Near-field Optical Microscope (or cm-THz-sSNOM) instrument is comprised three main equipment: (i) T...
We conducted a comprehensive study of the non-equilibrium dynamics Cooper pair breaking, quasiparticle (QP) generation, and relaxation in niobium (Nb) cut from superconducting radio-frequency (SRF) cavities, as well various Nb resonator films transmon qubits. Using ultrafast pump–probe spectroscopy, we were able to isolate coherence pair-breaking responses. Our results reveal both similarities notable differences temperature- magnetic-field-dependent SRF cavity thin-film samples. Moreover,...
Direct visualization and quantitative evaluation of charge filling in grain boundary (GB) traps hybrid metal halide perovskites require dynamic conductivity imaging simultaneously at the terahertz (THz) frequency nanometer (nm) spatial scales not accessible by conventional transport methods used thus far. Here, we apply a THz near-field nanoconductivity mapping to archetypal perovskite photovoltaic films demonstrate that it is powerful tool reveal distinct dielectric heterogeneity due...
Abstract The challenge underlying superconducting quantum computing is to remove materials bottleneck for highly coherent devices. nonuniformity and complex structural components in the circuits often lead local electric field concentration, charge scattering, dissipation ultimately decoherence. Here we visualize interface dipole heterogeneous distribution of individual Al/AlO x /Al junctions employed transmon qubits by broadband terahertz scanning near-field microscopy that enables...
We conducted a comprehensive study of the non-equilibrium dynamics Cooper pair breaking, quasiparticle (QP) generation, and relaxation in niobium (Nb) cut from superconducting radio-frequency cavities, as well various Nb resonator films transomon qubits. Using ultrafast pump-probe spectroscopy regime minimal condensate depletion, we were able to isolate coherence pair-breaking responses. Our results reveal both similarities notable differences temperature- magnetic field-dependent samples....
Terahertz scattering-type scanning near-field optical microscopy (THz-sSNOM) provides a noninvasive way to probe the low frequency conductivity of materials and characterize material compositions at nanoscale. However, potential capability atomic compositional analysis with THz nanoscopy remains largely unexplored. Here, we perform imaging spectroscopy on model rare-earth alloy lanthanum silicide (La-Si) which is known exhibit diverse structural phases. We identify subwavelength spatial...
One manifestation of light-Weyl fermion interaction is the emergence chiral magnetic effects under fields. Probing real space responses at terahertz (THz) scales challenging but highly desired, as local are less affected by topologically trivial inhomogeneity that ubiquitous in spatially averaged measurements. Here, we implement a cryogenic THz microscopy instrument field environment—a task only recently achieved. We explore technical approach this system and characterize field’s influence...
Abstract The fundamental challenge underlying superconducting quantum computing is to characterize heterogeneity and disorder that lead local electric field concentration, charge scattering, dissipation ultimately decoherence. It particularly challenging probe deep sub-wavelength distribution under electromagnetic wave coupling at individual nano-junctions correlate them with structural imperfections from interface boundary, ubiquitous in Josephson junctions used transmon qubits. A major...
We have developed a versatile near-field microscopy platform that can operate at high magnetic fields and below liquid-helium temperatures. use this to demonstrate an extreme terahertz (THz) nanoscope operation obtain the first cryogenic magneto-THz time-domain nano-spectroscopy/imaging temperatures as low 1.8 K of up 5 T simultaneously. Our scanning optical microscopy, or cm-SNOM, instrument comprises three main equipment: i) split pair cryostat with custom made insert for mounting SNOM...