A5063891943- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Iron-based superconductors research
- Advanced Thermodynamics and Statistical Mechanics
- Perovskite Materials and Applications
- Semiconductor Quantum Structures and Devices
- Rare-earth and actinide compounds
- Topological Materials and Phenomena
- Graphene research and applications
- Terahertz technology and applications
- Surface and Thin Film Phenomena
- Superconductivity in MgB2 and Alloys
- Quantum, superfluid, helium dynamics
- Molecular Junctions and Nanostructures
- Advanced Thermoelectric Materials and Devices
- Atomic and Subatomic Physics Research
- Photorefractive and Nonlinear Optics
- Electronic and Structural Properties of Oxides
- Spectroscopy and Quantum Chemical Studies
- 2D Materials and Applications
- Thermal Radiation and Cooling Technologies
- Magnetic properties of thin films
- Advanced Chemical Physics Studies
- Quantum Information and Cryptography
- Organic and Molecular Conductors Research
Ames National Laboratory
2019-2025
Iowa State University
2019-2025
United States Department of Energy
2020
Xiamen University
2015-2017
National Tsing Hua University
2012-2014
Intel (United States)
1981
Si-nanosheets (Si-NSs) have recently attracted considerable attention due to their potential as next-generation materials for electronic, optoelectronic, spintronic, and catalytic applications. Even though monolayer Si-NSs were first synthesized over 150 years ago via topotactic deintercalation of CaSi2, there is a lack consensus within the literature regarding structure optical properties this material. Herein, we provide conclusive evidence structural chemical produced by CaSi2 with cold...
We report terahertz (THz) light-induced second harmonic generation, in superconductors with inversion symmetry that forbid even-order nonlinearities. The THz emission vanishes above the superconductor critical temperature and arises from precession of twisted Anderson pseudospins at a multicycle, driving frequency is not allowed by equilibrium symmetry. explain microscopic physics dynamical breaking principle sub-THz-cycle using quantum kinetic modeling interplay between strong THz-lightwave...
Abstract The Higgs mechanism, i.e., spontaneous symmetry breaking of the quantum vacuum, is a cross-disciplinary principle, universal for understanding dark energy, antimatter and materials, from superconductivity to magnetism. Unlike one-band superconductors (SCs), conceptually distinct amplitude mode can arise in multi-band, unconventional via strong interband Coulomb interaction, but yet be accessed. Here we discover such hybrid demonstrate its control by light iron-based high-temperature...
Lightwave periodic driving of nearly dissipation-less currents has recently emerged as a universal control concept for both superconducting (SC) and topological electronics applications. While exciting progress been made towards THz-driven superconductivity, our understanding the interactions able to drive non-equilibrium pairing is still limited, partially due lack direct measurements high-order correlation functions. Such would exceed conventional single-particle spectroscopies...
Abstract Nonlinear interactions of spin-waves and their quanta, magnons, have emerged as prominent candidates for interference-based technology, ranging from quantum transduction to antiferromagnetic spintronics. Yet magnon multiplication in the terahertz (THz) spectral region represents a major challenge. Intense, resonant magnetic fields THz pulse-pairs with controllable phases amplitudes enable high order multiplication, distinct non-resonant nonlinearities such harmonic generation by...
A light-induced phase transition in a Dirac material offers insight into how these materials respond to periodic driving (that is, quantum back-and-forth motion), information necessary for topology-based computation and topological transistors.
We discover hidden Rashba fine structure in CH$_3$NH$_3$PbI$_3$ and demonstrate its quantum control by vibrational coherence through symmetry-selective vibronic (electron-phonon) coupling. Above a critical threshold of single-cycle terahertz pump field, Raman phonon mode distinctly modulates the middle excitonic states with {\em persistent} for more than ten times longer ones on two sides that predominately couple to infrared phonons. These beats, together first-principles modeling...
Emerging topological semimetals offer promise of realizing electronics enabled by terahertz (THz) current persistent against impurity scattering. Yet most fundamental issues remain on how to image nanoscale conductivity inhomogeneity. Here we show noninvasive and contactless mapping at THz-nm limit electronic heterogeneity nanostrip junctions in a Dirac material ZrTe5. A clear Fermion density transition, manifested as the exclusive THz contrast, is quantitatively analyzed profiled both sides...
We present a comprehensive theory of light-controlled multiband superconductivity, and apply it to predict distinctive signatures light-driven superconducting (SC) states in terahertz multidimensional coherent spectroscopy (THz-MDCS) experiments. first derive gauge-invariant Maxwell-Bloch equations for BCS superconductors with spatial fluctuations. consider driving electromagnetic fields determined self-consistently by Maxwell's equations. By calculating the THz-MDCS spectra measured...
Nonlinear interactions of spin-waves and their quanta, magnons, have emerged as prominent candidates for interference-based technology, ranging from quantum transduction to antiferromagnetic spintronics. Yet magnon multiplication in the terahertz (THz) spectral region represents a major challenge. Intense, resonant magnetic fields THz pulse-pairs with controllable phases amplitudes enable high order multiplication, distinct non-resonant nonlinearities such harmonic generation by below-band...
We calculate the efficiency at unified trade-off optimization criterion (the so-called maximum $\mathrm{\ensuremath{\Omega}}$ criterion) representing a compromise between useful energy and lost of heat engines operating two reservoirs different temperatures chemical potentials, demonstrate that linear coefficient 3/4 quadratic 1/32 are universal for under strong coupling symmetry conditions. It is further proved conclusions obtained here also apply to ecological criterion.
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 We present and benchmark a quantum computing approach to calculate the two-dimensional coherent spectrum (2DCS) of high-spin models. Our is based on simulating their real-time dynamics in presence several magnetic field pulses, which are spaced time. utilize adaptive variational simulation algorithm for study due its compact circuits, enables simulations over sufficiently long times achieve required resolution frequency space. Specifically, we consider an antiferromagnetic spin...
We report the discovery of helicity-dependent ultrafast photocurrent generation in organic-inorganic perovskite by measuring terahertz (THz) electric field emissions time-domain. find signatures circular photogalvanic effect (CPGE) where right circularly polarized light and left lead to different generation. The direction is also resolved polarization emitted THz pulses. Furthermore, we observe distinct wavelength-dependent, coherent phonon dynamics using pump-induced differential...
The fundamental challenge underlying superconducting quantum computing is to characterize heterogeneity and disorder in the circuits. These nonuniform distributions often 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 Josephson...
Topologically protected surface current is highly promising for next-generation low-dissipation and disorder-tolerant quantum electronics computing. Yet, electric transport from the co-existing bulk state dominates responses of Dirac state, especially at elevated temperatures relevant to technological applications. Here, we present an approach that convincingly showcases generation, disentanglement, precise control enduring charge carriers on a topological insulator, Bi2Se3, with high...
It will be shown in this paper that as a consequence of high-field stress on thin SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> films (70-200Å), two types charges are introduced into the oxide. Their spatial distribution and formation mechanisms first investigated. Then phenomenon electron trap generation owing to is discussed. Experimental techniques special precautions for seperating effects also described. The effect these...