A5071498092- Quantum and electron transport phenomena
- Semiconductor Quantum Structures and Devices
- Physics of Superconductivity and Magnetism
- Quantum optics and atomic interactions
- Spectroscopy and Quantum Chemical Studies
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Topological Materials and Phenomena
- Electronic and Structural Properties of Oxides
- Magneto-Optical Properties and Applications
- Iron-based superconductors research
- Advanced Condensed Matter Physics
- Mechanical and Optical Resonators
- Quantum Information and Cryptography
- 2D Materials and Applications
- ZnO doping and properties
- Gold and Silver Nanoparticles Synthesis and Applications
- Graphene research and applications
- Strong Light-Matter Interactions
- Quantum, superfluid, helium dynamics
- Molecular Junctions and Nanostructures
- Rare-earth and actinide compounds
- Laser-Matter Interactions and Applications
University of Alabama at Birmingham
2017-2025
University of Alabama
2023
Foundation for Research and Technology Hellas
2007-2018
University of Crete
2009-2018
FORTH Institute of Electronic Structure and Laser
2003-2012
University of California, Berkeley
2000-2007
Vanderbilt University
1996-2005
University of California, Santa Barbara
1999
Lawrence Berkeley National Laboratory
1999
Institut de Physique et Chimie des Matériaux de Strasbourg
1999
The recent discovery of topology-protected charge transport ultimate thinness on surfaces three-dimensional topological insulators (TIs) are breaking new ground in fundamental quantum science and transformative technology. Yet a challenge remains how to isolate disentangle helical spin the surface from bulk conduction. Here we show that selective midinfrared femtosecond photoexcitation exclusive intraband electronic transitions at low temperature underpins enhancement terahertz (THz) doped...
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...
Abstract How photoexcitations evolve into Coulomb-bound electron and hole pairs, called excitons, unbound charge carriers is a key cross-cutting issue in photovoltaics optoelectronics. Until now, the initial quantum dynamics following photoexcitation remains elusive hybrid perovskite system. Here we reveal excitonic Rydberg states with distinct formation pathways by observing multiple resonant, internal transitions using ultrafast terahertz quasi-particle transport. Nonequilibrium emergent...
Abstract The demand for disorder-tolerant quantum logic and spin electronics can be met by generating controlling dissipationless currents protected topology. Dirac fermions with helical spin-locking surface transport offer a way of achieving such goal. Yet, surface-bulk coupling lead to strong electron scattering bulk carriers phonons as well impurities, assisted dissipative channel, which results in “topological breakdown”. Here, we demonstrate that coherent lattice vibrations periodically...
We report on an ultrafast nonequilibrium phase transition with a strikingly long-lived martensitic anomaly driven by above-threshold single-cycle terahertz pulses peak field of more than 1 MV/cm. A nonthermal, terahertz-induced depletion low-frequency conductivity in Nb 3 Sn indicates increased gap splitting high-energy Γ 12 bands removal their degeneracies, which induces the above equilibrium temperature. In contrast, optical pumping leads to thermal melting. Such light-induced exhibits...
Abstract Light engineering of correlated states in topological materials provides a new avenue achieving exotic phases inaccessible by conventional tuning methods. Here we demonstrate light control correlation gaps model charge-density-wave (CDW) and polaron insulator (TaSe 4 ) 2 I recently predicted to be an axion insulator. Our ultrafast terahertz photocurrent spectroscopy reveals two-step, non-thermal melting polarons electronic CDW gap via the fluence dependence longitudinal circular...
We study the effect of Coulomb correlations on ultrafast optical dynamics small metal particles. demonstrate that a surface-induced dynamical screening electron-electron interactions leads to quasiparticle scattering with collective surface excitations. In noble-metal nanoparticles, it results in an interband resonant $d$ holes plasmons. show this size-dependent many-body manifests itself differential absorption for frequencies close plasmon resonance. particular, our self-consistent...
A model of a local orbital coupled through repulsive interactions to both the hybridizing and screening channels conduction band is solved by Wilson's renormalization group method. At particle-hole symmetry we find non-Fermi-liquid lines critical points when interaction in channel above value. Away from system displays two stable Fermi-liquid fixed different symmetries, separated non-Fermi liquid quantum point, mixed-valence regime. The behavior vicinity this point consistent with marginal...
A key prerequisite for low-threshold polariton lasing in organic or inorganic microcavity systems is the efficient population of lower ground state. Here, we report observation a resonant phonon-mediated relaxation process which gives rise to nonthermal with sub 100 fs build-up times. This mechanism manifested by discrete maxima angular-resolved photoluminescence intensity, corresponding shortening time at respective phonon resonances. The realization enhanced rates disordered J-aggregate...
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.
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...
The symmetry-topology interplay dictates how to define order parameters and classify material ordered phases. However, current understanding of this has been predominately approached from a one-sided perspective, with topological states being classified within the constraints imposed by specific fixed symmetries. Here we complete full circle demonstrating spontaneous symmetry breaking that results periodic alteration phases induced light in centrosymmetric Dirac ZrTe$_5$. distinguishing...