Field-Driven Dynamics of Correlated Electrons in LiH and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>NaBH</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>Revealed by Femtosecond X-Ray Diffraction

Juvé, Vincent; Holtz, Marcel; Zamponi, F.; Woerner, M.; Elsaesser, Thomas; Borgschulte, Andreas

doi:10.1103/physrevlett.111.217401

Cited by 32 publications

(20 citation statements)

References 41 publications

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“…Such parameters correspond to the experimental situation of Ref. 5 where field-induced quasi-instantaneous inter-ionic charge transfer has been studied in crystalline LiH. The integrated charge change Δ Q ( t ) around the H-atom [Fig.…”

Section: Results and Comparison With Experimental Datamentioning

confidence: 74%

Theoretical analysis of hard x-ray generation by nonperturbative interaction of ultrashort light pulses with a metal

Weißhaupt

Juvé

Holtz

et al. 2015

Structural Dynamics

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The interaction of intense femtosecond pulses with metals allows for generating ultrashort hard x-rays. In contrast to plasma theories, tunneling from the target into vacuum is introduced as electron generation step, followed by vacuum acceleration in the laser field and re-entrance into the target to generate characteristic x-rays and Bremsstrahlung. For negligible space charge in vacuum, the Kα flux is proportional to the incident intensity and the wavelength squared, suggesting a strong enhancement of the x-ray flux by mid-infrared driving pulses. This prediction is in quantitative agreement with experiments on femtosecond Cu Kα generation.

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Section: Results and Comparison With Experimental Datamentioning

confidence: 74%

Theoretical analysis of hard x-ray generation by nonperturbative interaction of ultrashort light pulses with a metal

Weißhaupt

Juvé

Holtz

et al. 2015

Structural Dynamics

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“…Generation of high harmonics even for the circularly polarized laser fields is consistent with scattering from neighbouring sites in the crystal. These results open up the possibility of measuring field-induced charge flow 23,24,28,29 and imaging atomic orbitals in solids 30 , which we discuss in the Methods. In analogy to the conventional electron diffraction methods, solidstate HHG allows us to use electrons that are already present in the bulk matter to image the ångström-scale structure of the condensed matter.…”

mentioning

confidence: 99%

“…Therefore, the strong anisotropy we observe cannot be explained just from tunnelling rates at the zone centre. In MgO, a large electronegativity gradient exists along the Mg-O, 100 bonding direction (Mg ++ /O −− ); therefore, this could be a preferred crystallographic direction for field-induced charge transfer 23,24 . To analyse this possibility at the microscopic level, we consider semi-classical electron trajectory calculations in the crystal.…”

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confidence: 99%

Anisotropic high-harmonic generation in bulk crystals

2016

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The microscopic valence electron density determines the optical, electronic, structural and thermal properties of materials. However, current techniques for measuring this electron charge density are limited: for example, scanning tunnelling microscopy is confined to investigations at the surface, and electron di raction requires very thin samples to avoid multiple scattering 1 . Therefore, an optical method is desirable for measuring the valence charge density of bulk materials. Since the discovery of high-harmonic generation (HHG) in solids 2 , there has been growing interest in using HHG to probe the electronic structure of solids 3-11 . Here, using single-crystal MgO, we demonstrate that high-harmonic generation in solids is sensitive to interatomic bonding. We find that harmonic e ciency is enhanced (diminished) for semi-classical electron trajectories that connect (avoid) neighbouring atomic sites in the crystal. These results indicate the possibility of using materials' own electrons for retrieving the interatomic potential and thus the valence electron density, and perhaps even wavefunctions, in an all-optical setting.High-harmonic generation (HHG) in bulk crystal is attributed to the sub-cycle electronic motion driven by an intense laser field [2][3][4][5][6][7][8][9][10][11] . There has been a growing interest in utilizing HHG to probe the electronic structure of solids 8,9,11 . Vampa et al. reconstructed the momentum-dependent bandgap of ZnO along the -M direction using HHG from a two-colour driving field 11 . Luu et al. retrieved the energy dispersion of the lowest conduction band of SiO 2 assuming that the harmonics are produced by the intraband currents 8 . The dependence of solid-state HHG on the coupling of multiple electronic bands has also been identified with the production of even harmonics in GaSe 9 and the emergence of a second plateau in rare-gas solids 12 . These findings show the possibility of using solidstate HHG to probe the electronic band structures in solids, but the analyses are so far limited to one dimension. For a complete electronic structure, it is desirable to exploit the microscopic process to measure the periodic potential in three dimensions (real space). This is analogous to tomographic imaging of a molecule, where the three-dimensional spatial information (that is, orbital wavefunction) of the target molecule is extracted [13][14][15] . Those measurement techniques are based critically on the dependence of HHG efficiency on molecular alignment with respect to the laser field 16 .In this letter, we demonstrate the strong sensitivity of HHG to the atomic-scale structure in the cubic wide-bandgap crystal MgO. First, using a linearly polarized field, we measure a highly anisotropic angular distribution in high-harmonic signal-despite the isotropic linear and weakly anisotropic nonlinear optical properties of the cubic crystal in the perturbative regime 17 . Second, we observe a strong ellipticity dependence of the HHG yield similar to the gas-phase HHG 18 for small elliptic...

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“…90,91 The recent implementation of ultrafast x-ray powder diffraction 53 which provides time resolved diffraction patterns consisting of up to 40 Debye-Scherrer rings, has allowed for creating the first transient electron density maps with a time resolution of 100 fs. Such pioneering work has given new insight into field-driven electron relocations 57,58 and the interplay of lattice and electron motions in ionic crystals, 55,56 as well as in elementary chemical processes such as hydrogen transfer. 54 The change of diffracted intensity I hkl (t) = I hkl (t) − I 0 hkl (I 0 hkl : intensity diffracted without excitation) integrated over the Debye-Scherrer ring (hkl) is given by…”

Section: B Transient Electron Density Mapsmentioning

confidence: 99%

“…52 Up to 40 reflections have been detected simultaneously with the powder diffraction method for polycrystalline samples, [53][54][55][56][57][58][59] implemented with laser-driven plasma sources. Powder diffraction patterns consist of many Debye-Scherrer rings originating from crystallites in the powder with a random orientation of the reciprocal lattice vector G hkl .…”

Section: B X-ray Probes Of Ultrafast Structural Dynamicsmentioning

confidence: 99%

Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data

Zhu

Yarkony

2014

The Journal of Chemical Physics

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A recently reported algorithm for representing adiabatic states coupled by conical intersections using a quasi-diabatic state Hamiltonian in four and five atom systems is extended to treat nonadiabatic processes in considerably larger molecules. The method treats all internal degrees of freedom and uses electronic structure data from ab initio multireference configuration interaction wave functions with nuclear configuration selection based on quasi-classical surface hopping trajectories. The method is shown here to be able to treat ∼30 internal degrees of freedom including dissociative and large amplitude internal motion. Two procedures are introduced which are essential to the algorithm, a null space projector which removes basis functions from the fitting process until they are needed and a partial diagonalization technique which allows for automated, but accurate, treatment of the vicinity of extended seams of conical intersections of two or more states. These procedures are described in detail. The method is illustrated using the photodissociaton of phenol, C6H5OH(${\rm \tilde X}{}^{1} A^{\prime} $X̃1A′) + hv → C6H5OH($\tilde A{}^{1} A^{\prime} $Ã1A′, ${\rm \tilde B}{}^{\rm 1}{\rm A^{\prime \prime} }$B̃1A′′) → C6H5O(${\rm \tilde X}{}^2{\rm B}_1$X̃2B1, ${\rm \tilde A}{}^2{\rm B}_2$Ã2B2) + H as a test case. Ab initio electronic structure data for the 1,2,31A states of phenol, which are coupled by conical intersections, are obtained from multireference first order configuration interaction wave functions. The design of bases to simultaneously treat large amplitude motion and dissociation is described, as is the ability of the fitting procedure to smooth the irregularities in the electronic energies attributable to the orbital changes that are inherent to nonadiabatic processes.

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Field-Driven Dynamics of Correlated Electrons in LiH andNaBH4Revealed by Femtosecond X-Ray Diffraction

Cited by 32 publications

References 41 publications

Theoretical analysis of hard x-ray generation by nonperturbative interaction of ultrashort light pulses with a metal

Theoretical analysis of hard x-ray generation by nonperturbative interaction of ultrashort light pulses with a metal

Anisotropic high-harmonic generation in bulk crystals

Fitting coupled potential energy surfaces for large systems: Method and construction of a 3-state representation for phenol photodissociation in the full 33 internal degrees of freedom using multireference configuration interaction determined data

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