Probing ultrafast spin-relaxation and precession dynamics in a cuprate Mott insulator with 7-fs optical pulses

Abstract

A charge excitation in a two-dimensional Mott insulator is strongly coupled with the surrounding spins, which is observed as magnetic-polaron formations of doped carriers and a magnon sideband in the Mott-gap transition spectrum. However, the dynamics related to the spin sector are difficult to measure. Here, we show that pump-probe reflection spectroscopy with 7-fs laser pulses can detect the optically induced spin dynamics in Nd${}_2$CuO${}_4$, a cuprate Mott insulator. The bleaching signal at the Mott-gap transition is enhanced at $\sim$18 fs, which corresponds to the spin-relaxation time in magnetic-polaron formations and is characterized by the exchange interaction. More importantly, ultrafast coherent oscillations appear in the time evolutions of the reflectivity changes, and their frequencies (1400-2700 cm${}^{-1}$) are equal to the probe energy measured from the Mott-gap transition peak. These oscillations originate from interferences between charge excitations with two magnons and provide direct evidence for charge-spin coupling.

arXiv comment20 pages including 4 figures (Supplementary materials: 11 pages including 4 figures)

References in corpus (14)

• Correlated Electrons in High Temperature Superconductors
• High-energy spin and charge excitations in electron-doped copper oxide superconductors
• Polaronic behavior of undoped high-Tc cuprates
• Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates
• Ultrafast charge recombination in photoexcited Mott-Hubbard insulator
• Superexchange coupling and spin susceptibility spectral weight in undoped monolayer cuprates
• Mechanism of Ultrafast Relaxation of a Photo-Carrier in Antiferromagnetic Spin Background
• Witnessing the formation and relaxation of massive quasi-particles in a strongly correlated electron system
• Ultra-fast photo-carrier relaxation in Mott insulators with short-range spin correlations
• Charge Recombination in Undoped Cuprates
• Photo-enhanced antinodal conductivity in the pseudogap state of high Tc cuprates
• Quantum Dynamics of a Driven Correlated System Coupled to Phonons
• Ultrafast carrier localisation in the pseudogap state of cuprate superconductors from coherent quench experiments
• Transient Carrier Dynamics in a Mott Insulator with Antiferromagnetic Order

Cited by in corpus (9)

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• Ultrafast magnetic dynamics in insulating YBa${}_2$Cu${}_3$O${}_{6+x}$ revealed by time resolved two-magnon Raman Scattering
• A photo-induced strange metal with electron and hole quasi-particles
• Persistent coherence of quantum superpositions in an optimally doped cuprate revealed by 2D spectroscopy
• Ultrafast transient interference in pump-probe spectroscopy of band and Mott insulators
• Many-body recombination in insulating cuprates
• Excited States beyond Mott Gap in Half-Filled-Band Hubbard Model
• Spin-charge correlations in finite one-dimensional multi-band Fermi systems