Ultrafast Frustration-Breaking and Magnetophononic Driving of Singlet Excitations in a Quantum Magnet

Abstract

Ideal magnetic frustration forms the basis for the emergence of exotic quantum spin states that are entirely nonmagnetic. Such singlet spin states are the defining feature of the Shastry-Sutherland model, and of its faithful materials realization in the quantum antiferromagnet SrCu${}_2$(BO${}_3$)${}_2$. To address these states on ultrafast timescales, despite their lack of any microscopic order parameter, we introduce a nonlinear magnetophononic mechanism to alter the quantum spin dynamics by driving multiple optical phonon modes coherently and simultaneously. We apply intense terahertz pulses to create a nonequilibrium modulation of the magnetic interactions that breaks the ideal frustration of SrCu${}_2$(BO${}_3$)${}_2$, such that previously forbidden physics can be driven in a coherent manner. Specifically, this driving populates a purely magnetic excitation, the singlet branch of the two-triplon bound state, by resonance with the difference frequency of two pumped phonons. Our results demonstrate how light-driven phonons can be used for the ultrafast and selective manipulation of interactions in condensed matter, even at frequencies far from those of the pump spectrum, offering valuable additional capabilities for the dynamical control of quantum many-body phenomena.

21 pages, 13 figures

References in corpus (11)

• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Nonthermal pathways to ultrafast control in quantum materials
• Quantum magnetism and criticality
• Quantum Magnets under Pressure: Controlling Elementary Excitations in TlCuCl3
• Nonlinear light-matter interaction at terahertz frequencies
• Temporal and spectral fingerprints of ultrafast all-coherent spin switching
• Quantum and classical criticality in a dimerized quantum antiferromagnet
• A quantum magnetic analogue to the critical point of water
• Incomplete devil's staircase in the magnetization curve of SrCu2(BO3)2
• Correlated decay of triplet excitations in the Shastry-Sutherland compound SrCu${}_2$(BO${}_3$)${}_2$
• Strong-coupling magnetophononics: Self-blocking, phonon-bitriplons, and spin-band engineering

Cited by in corpus (10)

• Spin high-harmonic generation through terahertz laser-driven phonons
• Phonon-driven multipolar dynamics in a spin-orbit coupled Mott insulator
• Dynamical phase transition in a strongly hybridized phonon-triplon chain
• Triplons, triplon pairs and dynamical symmetries in laser-driven Shastry-Sutherland magnets
• Pulsed Magnetophononics in Gapped Quantum Magnets
• Magnetic and phononic dynamics in the two-ladder quantum magnet (C5H9NH3)2CuBr4
• Evidence for spin liquid behavior in the frustrated three-dimensional $S=1/2$ Heisenberg garnet NaCa${}_2$Cu${}_2$(VO${}_4$)${}_3$
• Phonon spectrum in the spin-Peierls phase of CuGeO${}_3$
• $SU(N)$ spin-phonon simulations of Floquet dynamics in spin $S>1/2$ Mott insulators
• Terahertz light driven coherent excitation of a zone-folded Raman-active phonon mode in the Spin-Ladder System ${\alpha }^{\prime }$-NaV${}_2$O${}_5$