Abstract
With a combination of numerical methods, including quantum Monte Carlo, exact diagonalization, and a simplified dynamical mean-field model, we consider the attosecond charge dynamics of electrons induced by strong-field laser pulses in two-dimensional Mott insulators. The necessity to go beyond single-particle approaches in these strongly correlated systems has made the simulation of two-dimensional extended materials challenging, and we contrast their resulting high-harmonic emission with more widely studied one-dimensional analogues. As well as considering the photo-induced breakdown of the Mott insulating state and magnetic order, we also resolve the time and ultra-high-frequency domains of emission, which are used to characterize both the photo-transition, and the sub-cycle structure of the electron dynamics. This extends simulation capabilities and understanding of the photo-melting of these Mott insulators in two dimensions, at the frontier of attosecond non-equilibrium science of correlated materials.
Highlights
The non-linear response of a material under a strong driving field is increasingly being exploited for the high-harmonic generation (HHG) of coherent light, providing a powerful window into science on the shortest timescales[1]
Simple phenomenological models for the charge dynamics which lead to this HHG have been proposed for atomic systems[10,11,12,13], with this more recently being extended to simple semiconductors, based on a fixed bandstructure and the build-up of inter and intra-band electronic currents[14,15,16], where HHG was demonstrated experimentally only in the last decade[14,17,18]
The system is subject to a monochromatic driving field with frequency ωL and vector potential given by AðtÞ 1⁄4 E0=ωLsin2ðωLt=2NcÞ sinðωLtÞ, where E0 is the peak amplitude and Nc = 10 is the number of cycles
Summary
The non-linear response of a material under a strong driving field is increasingly being exploited for the high-harmonic generation (HHG) of coherent light, providing a powerful window into science on the shortest timescales[1] This has allowed for recent advances, including probes of attosecond electron dynamics[2,3], optical imaging of band structures[4], and control and manipulation of quantum phases[5,6,7,8], as well as answering some of the fundamental questions regarding the nature of decoherence in quantum systems[9]. HHG and driving fields in strongly correlated materials are far from understood, and is emerging as a key research challenge in computational nonequilibrium science
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