A5042955369- Strong Light-Matter Interactions
- 2D Materials and Applications
- Iron-based superconductors research
- Physics of Superconductivity and Magnetism
- Thermal Radiation and Cooling Technologies
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
- Advanced Condensed Matter Physics
- Semiconductor Quantum Structures and Devices
- Graphene research and applications
- Superconductivity in MgB2 and Alloys
- Quantum and electron transport phenomena
- Quantum many-body systems
- Particle physics theoretical and experimental studies
- Quantum Information and Cryptography
- Cosmology and Gravitation Theories
- Inorganic Chemistry and Materials
- Perovskite Materials and Applications
- Quantum optics and atomic interactions
- Magnetic and transport properties of perovskites and related materials
- Nonlinear Optical Materials Research
- Corporate Taxation and Avoidance
- Ammonia Synthesis and Nitrogen Reduction
- Photonic and Optical Devices
- Rare-earth and actinide compounds
University of Exeter
2022-2025
Henry Royce Institute
2020-2022
University of Manchester
2022
Argonne National Laboratory
2016-2019
University of Southern California
2013
Beijing Graphene Institute
2012
National Tsing Hua University
2007
Abstract Rydberg excitons (analogues of atoms in condensed matter systems) are highly excited bound electron-hole states with large Bohr radii. The interaction between them as well exciton coupling to light may lead strong optical nonlinearity, applications sensing and quantum information processing. Here, we achieve effective photon–photon interactions (Kerr-like nonlinearity) via the blockade phenomenon hybridisation photons forming polaritons a Cu2O-filled microresonator. Under pulsed...
SrxBi2Se3 and the related compounds CuxBi2Se3 NbxBi2Se3 have attracted considerable interest, as these materials may be realizations of unconventional topological superconductors. Superconductivity with Tc ~3 K in arises upon intercalation Sr into layered insulator Bi2Se3. Here we elucidate anisotropy normal superconducting state Sr0.1Bi2Se3 angular dependent magnetotransport thermodynamic measurements. High resolution x-ray diffraction studies underline high crystalline quality samples. We...
Spontaneous rotational-symmetry breaking in the superconducting state of doped $\mathrm{Bi}_2\mathrm{Se}_3$ has attracted significant attention as an indicator for topological superconductivity. In this paper, high-resolution calorimetry single-crystal $\mathrm{Sr}_{0.1}\mathrm{Bi}_2\mathrm{Se}_3$ provides unequivocal evidence a two-fold rotational symmetry gap by \emph{bulk thermodynamic} probe, fingerprint nematic The extremely small specific heat anomaly resolved with our high-sensitivity...
Van der Waals magnets are an emergent material class of paramount interest for fundamental studies in coupling light with matter excitations, which uniquely linked to their underlying magnetic properties. Among these materials, the semiconductor CrSBr is possibly a first playground where we can study simultaneously interaction photons, magnons, and excitons at quantum level. Here demonstrate coherent macroscopic phase, bosonic condensation exciton-polaritons, emerges flake embedded fully...
<title>Abstract</title> Ultrafast all-optical logic devices based on nonlinear light-matter interactions hold the promise to overcome speed limitations of conventional electronic devices. Strong coupling excitons and photons inside an optical resonator enhances such generates new polariton states which give access unique phenomena, as Bose-Einstein condensation, used for ultrafast transistors. However, reach threshold condensation high quality factors pulse energies are required. Here we...
We develop a full microscopic theory for nonlinear phase space filling (NPSF) in strongly coupled two-dimensional polaritonic lattices. Ubiquitous experiments, the theoretical description of NPSF, also known as optical saturation, remains limited to perturbative treatment and homogeneous samples. In this study, we go beyond existing discover broad scope regimes where NPSF crucially modifies response. Studying quantum effects non-bosonicity, cooperative light-matter coupling, Coulomb...
The competing ground states of bilayer graphene are studied by applying renormalization group techniques to a honeycomb lattice with nearest neighbor hopping. In the absence interactions, Fermi surface this model at half-filling consists two nodal points momenta $\mathbf{K}$, ${\mathbf{K}}^{\ensuremath{'}}$, where conduction band and valence touch each other, yielding semimetal. Since near these energy dispersion is quadratic perfect particle-hole symmetry, excitonic instabilities inevitable...
We investigate the influence of Landau quantization on superconducting instability for a pure layered superconductor in magnetic field directed perpendicular to layers. demonstrate that corrections Cooper-pairing kernel with finite Zeeman spin splitting promote formation nonuniform state which order parameter is periodically modulated along field, i.e., between layers (Fulde-Ferrell-Larkin-Ovchinnikov [FFLO] state). The conventional uniform experiences such quantization-induced FFLO at low...
We perform a $\mathbf{k \cdot p}$ theory analysis of the spectra lowest energy and excited states excitons in few-layer atomically thin films InSe taking into account in-plane electric polarizability film influence encapsulation environment. For thinner films, lowest-energy state exciton is weakly indirect momentum space, with its dispersion showing minima at layer-number-dependent wave number, due to an inverted edge relatively flat topmost valence band branch spectrum we compute activation...
We build a microscopic model to study the intralayer and interlayer superexchange due electrons hopping in chromium trihalides ($\mathrm{Cr}{X}_{3}$, $X=$ Cl, Br, I). In evaluating superexchange, we identify relevant intermediate excitations hopping. our study, find that hole-pair $p$ orbitals on $X$ ion play crucial role mediating various types of exchange interactions. particular, antiferromagnetic may be realized by hole-pair-mediated superexchange. Interestingly, also these virtual...
We construct a microscopic model based on superexchange theory for moir\'e bilayer in chromium trihalides $(\mathrm{Cr}{X}_{3},$ $X=\mathrm{Br},\mathrm{I})$. In particular, we derive analytically the interlayer Heisenberg exchange and Dzyaloshinskii-Moriya interaction with arbitrary distances $(\mathbit{x})$ between spins. Importantly, our takes into account sliding twisting geometries $X\text{\ensuremath{-}}X$ hopping processes. Our approach can directly access $\mathbit{x}$-dependent...
We investigate the onset of superconductivity in magnetic field for a clean two-dimensional multiple-band superconductor vicinity Lifshitz transition when one bands is very shallow. Due to small number carriers this band, quasiclassical Werthamer-Helfand approximation breaks down and Landau quantization has be taken into account. found that temperature TC2(H) giant oscillations resonantly enhanced at fields corresponding full occupancy levels shallow band. This enhancement especially...
Electronic nematicity plays important role in iron-based superconductors. These materials have layered structure and theoretical description of their magnetic nematic transitions has been well established two-dimensional approximation, i.e., when the layers can be treated independently. However, interaction between iron mediated by electron tunneling may cause non-trivial three-dimensional behavior. Starting from simplest model for orbital a single layer, we investigate influence interlayer...
We study the associated production of a very light pseudoscalar Higgs boson with pair charginos. The novel signature involves charged leptons from chargino decays and photons decay, plus large missing energy at LHC ILC. signal may help us to distinguish NMSSM MSSM, provided that experiment can resolve two decay boson.
In this paper, instabilities of the isotropic metallic phase in iron pnictides are investigated. The relevant quartic fermionic interaction terms model identified using space arguments. Using functional integral formalism, a Hubbard-Stratonovich transformation is used to decouple these terms. This procedure introduces several bosonic fields which describe low-energy collective modes system. By studying behavior modes, possible instability found forward scattering channel driven by magnetic...
We explore superconducting instability for a clean two-band layered superconductor with deep and shallow bands in the magnetic field applied perpendicular to layers. In band, quasiclassical approximation is not applicable, Landau quantization has be accounted exactly. The electronic spectrum of this band composed one-dimensional Landau-level minibands. With increasing system experiences series Lifshitz transitions when chemical potential enters exits These profoundly influence shape upper...
Rydberg excitons (analogues of atoms in condensed matter systems) are highly excited bound electron-hole states with large Bohr radii. The interaction between them as well exciton coupling to light may lead strong optical nonlinearity, applications sensing and quantum information processing. Here, we achieve effective photon-photon interactions (Kerr-like nonlinearity) via the blockade phenomenon hybridisation photons forming polaritons a Cu$_2$O-filled microresonators. Under pulsed resonant...
We develop a microscopic theory for nonlinear optical response of moir\'e exciton-polaritons in bilayers transition metal dichalcogenides (TMDs). Our allows to study the tunnel-coupled intralayer and interlayer excitonic modes wide range twist angles ($\theta$), external electric field, light-matter coupling, providing insights into hybridization regime inaccessible before. Specifically, we account Umklapp scattering processes two responsible enhanced nonlinearity, show that it is crucial...
Ultrafast all-optical logic devices based on nonlinear light-matter interactions hold the promise to overcome speed limitations of conventional electronic devices. Strong coupling excitons and photons inside an optical resonator enhances such generates new polariton states which give access unique phenomena, as Bose-Einstein condensation, used for ultrafast transistors. However, pulse energies required pump range from tens hundreds pJ, making them not competitive with Here we introduce a...
Layered 2D halide perovskites are chemically synthesized realizations of quantum well stacks with giant exciton oscillator strengths, tunable emission spectra and very large binding energies. While these features render a promising platform for room-temperature polaritonics, bosonic condensation polariton lasing in have so far remained elusive at ambient conditions. Here, we demonstrate cavity exciton-polariton mechanically exfoliated crystals the Ruddlesden-Popper iodide perovskite...
Sr$_x$Bi$_2$Se$_3$ and the related compounds Cu$_x$Bi$_2$Se$_3$ Nb$_x$Bi$_2$Se$_3$ have attracted considerable interest, as these materials may be realizations of unconventional topological superconductors. Superconductivity with T$_c$ ~ 3 K in arises upon intercalation Sr into layered insulator Bi$_2$Se$_3$. Here we elucidate anisotropy normal superconducting state Sr$_{0.1}$Bi$_2$Se$_3$ angular dependent magnetotransport thermodynamic measurements. High resolution x-ray diffraction studies...
We develop a theoretical description of Coulomb interactions between trions (charged excitons) that define nonlinear optical response in doped two-dimensional semiconductors. First, we formulate microscopic theory trion-trion based on composite nature these particles, and account for all possible exchange processes. Next, calculate numerically the trion binding energies corresponding three-body wavefunctions using basis set with high expressivity. Then, obtained matrix elements two-trion...
We construct a microscopic model based on superexchange theory for moiré bilayer in chromium trihalides (Cr$X_3$, $X=$Br, I). In particular, we derive analytically the interlayer Heisenberg exchange and Dzyaloshinskii-Moriya interaction with arbitrary distances (x) between spins. Importantly, our takes into account sliding twisting geometries $X$-$X$ hopping processes. Our approach can directly access $x$-dependent without large unit-cell calculations. argue that deducing by various bilayers...