Probing photoinduced rearrangements in the NdNiO3 magnetic spiral with polarization-sensitive ultrafast resonant soft x-ray scattering

Abstract

We use resonant soft x-ray diffraction to track the photoinduced dynamics of the antiferromagnetic structure in a NdNiO 3 thin film. Femtosecond laser pulses with a photon energy of 0.61 eV, resonant with electron transfer between long-bond and short-bond nickel sites, are used to excite the material and drive an ultrafast insulatormetal transition. Polarization-sensitive soft x-ray diffraction, resonant to the nickel L 3 edge, then probes the evolution of the underlying magnetic spiral as a function of time delay with 80 ps time resolution. By modeling the azimuthal dependence of the scattered intensity for different linear x-ray polarizations, we benchmark the changes of the local magnetic moments and the spin alignment. The measured changes are consistent with a reduction of the long-bond site magnetic moments and an alignment of the spins towards a more collinear structure at early time delays.

A New Era of Quantum Materials Mastery and Quantum Simulators In and Out of Equilibrium

“…On the experimental side it is not straightforward to generate such strong perturbing pulses in a controlled fashion. Recently, advances in light sources received a tremendous experimental push with key developments being made in ultrafast spectroscopies, as well as within creating tailored strong laser sources that can specifically drive desired excitations in materials in an almost surgical way [5,[50][51][52][53][54][55][56][57][58][59][60][61][62]. As a consequence structural light is one of the leading experimental vehicles to achieve such nonequilibrium control over solids, not least because it comes in many flavors: We can differentiate between using light in the classical as well as in the deeply quantum limit to achieve control each with and without carrying intrinsic angular momentum; the latter opening up the blossoming field of chiral light sources.…”

Photo-induced phase-transitions in complex solids

“…This is exemplified in strongly correlated transition-metal oxides, such as manganites and nickelates. While multipleorder parameters, linked to structural, electronic, and magnetic degrees of freedom, are already present during thermal phase-transitions, the selective perturbation of these order parameters through optical excitations leads to new types of transformations [32,[39][40][41][42][43][44]. In the Weyl semimetal system WTe 2 , shear strain is coupled to ultrafast switching of topological invariants [12].…”

“…While multiple-order parameters, linked to structural, electronic, and magnetic degrees of freedom, are already present during thermal phase-transitions, the selective perturbation of these order parameters through optical excitations leads to new types of transformations. 32,39–44 In the Weyl semimetal system WTe 2 , shear strain is coupled to ultrafast switching of topological invariants. 12 The form of the PIPTs depends sensitively on the details of the materials system.…”

Nonthermal breaking of magnetic order via photogenerated spin defects in the spin-orbit coupled insulator Sr3Ir2O7

“…However, finding unique optical markers for antiferromagnetism is particularly challenging, as the lack of net magnetic moment hinders the use of traditional magneto-optical methodologies. Such difficulty has stimulated the development of methods to probe it on fast timescales, but many require access to large-scale user facilities, which makes collecting full datasets difficult, and often, sensitivity to magnetic order comes at the expense of sensitivity to other degrees of freedom [2,[9][10][11][12][13][14][15][16].…”