Search

Condensed matter research has seen prominent recent advances in ultrafast optical manipulation and topological materials. Here, Sentef et al. simulate the development of the photoemission-measured band structure of Floquet states in graphene excited by low-frequency circularly-polarized laser pulses.

Time- and angle-resolved photoemission spectroscopy now resolves the long-sought avoided crossing in light-driven graphene, establishing a practical recipe for Floquet band engineering and sharpening prospects for light-induced topology in quantum materials.

A new platform making use of hexagonal boron nitride interfaced with the molecular superconductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br is demonstrated for realizing cavity-altered materials, confirmed by magnetic force microscopy and nano-optical measurements.

The feasibility of Floquet engineering in graphene has been called into question due to its fast decoherence processes. Measurements of graphene’s photoemission spectrum now support the generation of Floquet states in this material.

The forces between electrons and nuclei in solids are difficult to image directly. A study shows that these forces can instead be indirectly imaged using the light emitted when the electrons are subjected to a strong laser field.

Integrating an electronic device with a cavity can cause the electrons to couple to photons strongly enough to form hybrid modes. Now, the cavity effects induced by intrinsic graphite gates are shown to modify the low-energy properties of graphene.

Distinguishing band and Mott insulators experimentally represents a longstanding challenge. Here, the authors demonstrate a momentum-resolved signature of a dimerized Mott-insulator in the out-of-plane spectral function of Nb₃Br₈.

The authors theoretically propose a simple microscopic mechanism for light-induced superconductivity based on a boson coupled to an electronic interband transition. The electron-electron attraction needed for the superconductivity can be resonantly amplified when the boson’s frequency is close to the energy difference between the two electronic bands. The model can be engineered using a 2D heterostructure.

Topological states may emerge in nonequilibrium but the mechanisms are much less understood. Here Topp et al. propose a nonequilibrium route to obtain the magnetic Weyl semimetallic phase in pyrochlore iridates by ultrafast modification of the effective electron-electron interactions with short laser pulses.

The build-up and dephasing of Floquet-–Bloch bands is visualized in both subcycle band-structure videography and quantum theory, revealing the interplay of strong-field intraband and interband excitations in a non-equilibrium Floquet picture.

Precision measurement of the dynamical magnetoelectric coupling in an exfoliated van der Waals multiferroic shows a giant natural optical activity at terahertz frequencies.

Creating and controlling topological states of matter has become a central goal in condensed matter physics. Here, the authors report a predictive Floquet engineering of various topological phases in Na₃Bi by using femtosecond laser pulses.

Mobile excitons in metals have been elusive, as screening usually suppresses their formation. Here, the authors demonstrate such mobile bound states in quasi-one-dimensional metallic TaSe₃, taking advantage of its low dimensionality and carrier density.

For solid-state experiments, exactly solvable quantum light matter models, where the quantum nature of light is relevant, are scarce. Here, the authors introduce an exactly solvable model, where a one-dimensional tight-binding chain is coupled to a single cavity mode and derive analytic expressions for the ground state, where the photons are squeezed due to the light-matter coupling.

Strong light–matter coupling in quantum cavities provides a pathway to break fundamental materials symmetries, like time-reversal symmetry in chiral cavities. This Comment discusses the potential to realize non-equilibrium states of matter that have so far been only accessible in ultrafast and ultrastrong laser-driven materials.

The impulsively driven antiferromagnetic Mott insulator is a model quantum many-body system predicted to realize exotic transient phenomena, however its exploration in far-from equilibrium regimes remains experimentally challenging. Here, the authors use a combination of second harmonic optical polarimetry and coherent magnon spectroscopy to investigate the ultrafast non-equilibrium dynamics of the Mott insulator Sr₂IrO₄ and find evidence of a far-from-equilibrium critical regime where static and dynamic critical behaviour decouple and which could be present in a number of other quantum materials.