The observation and control of interweaving spin, charge, orbital, and structural degrees of freedom in materials on ultrafast time scales reveal exotic quantum phenomena and enable new active forms of nanotechnology. Bonding is the prime example of the relation between electronic and nuclear degrees of freedom. We report direct evidence illustrating that photoexcitation can be used for ultrafast control of the breaking and recovery of bonds in solids on unprecedented time scales, near the limit for nuclear motions. We describe experimental and theoretical studies of IrTe using femtosecond electron diffraction and density functional theory to investigate bonding instability. Ir-Ir dimerization shows an unexpected fast dissociation and recovery due to the filling of the antibonding d orbital. Bond length changes of 20% in IrTe are achieved by effectively addressing the bonds directly through this relaxation process. These results could pave the way to ultrafast switching between metastable structures by photoinduced manipulation of the relative degree of bonding in this manner.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6063536 | PMC |
http://dx.doi.org/10.1126/sciadv.aar3867 | DOI Listing |
Nanoscale
January 2025
Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J.J.Thomson Avenue, Cambridge CB3 0HE, UK.
Benefiting from improved stability due to interlayer van der Waals interactions, few-layer fullerene networks are experimentally more accessible compared to monolayer polymeric C. However, there is a lack of systematic theoretical studies on the material properties of few-layer C networks. Here, we compare the structural, electronic and optical properties of bilayer and monolayer fullerene networks.
View Article and Find Full Text PDFChaos
January 2025
Department of Control Theory, Scientific and Educational Mathematical Center "Mathematics of Future Technologies", Nizhny Novgorod State University, Gagarin Av. 23, Nizhny Novgorod 603022, Russia.
We consider the effect of the emergence of chimera states in a system of coexisting stationary and flying-through in potential particles with an internal degree of freedom determined by the phase. All particles tend to an equilibrium state with a small number of potential wells, which leads to the emergence of a stationary chimera. An increase in the number of potential wells leads to the emergence of particles flying-through along the medium, the phases of which form a moving chimera.
View Article and Find Full Text PDFStruct Dyn
January 2025
Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
Sub-ångström spatial resolution of electron density coupled with sub-femtosecond to few-femtosecond temporal resolution is required to directly observe the dynamics of the electronic structure of a molecule after photoinitiation or some other ultrafast perturbation, such as by soft X-rays. Meeting this challenge, pushing the field of quantum crystallography to attosecond timescales, would bring insights into how the electronic and nuclear degrees of freedom couple, enable the study of quantum coherences involved in molecular dynamics, and ultimately enable these dynamics to be controlled. Here, we propose to reach this realm by employing convergent-beam x-ray crystallography with high-power attosecond pulses from a hard-x-ray free-electron laser.
View Article and Find Full Text PDFVector modes are well-defined field distributions with spatially varying polarization states, rendering them irreducible to the product of a single spatial mode and a single polarization state. Traditionally, the spatial degree of freedom of vector modes is constructed using two orthogonal modes from the same family. Here, we introduce a novel class of vector modes whose spatial degree of freedom is encoded by combining modes from both the Hermite- and Laguerre-Gaussian families, ensuring that the modes are shape-invariant upon propagation.
View Article and Find Full Text PDFThe control of temporal noise of the pump could add an additional degree of freedom to manipulate the spectrum of continuous-wave (CW) pumped SC generation. In this paper, we experimentally tailor the CW-pumped supercontinuum (SC) generation in a cascaded Raman random fiber laser (CRRFL) based on a 1 µm pump with tunable temporal dynamics. The pump is based on a spectrally filtered ytterbium-doped random fiber laser (YRFL) seed laser, which can be amplified to a 10 W level with the tunable temporal noise.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!