Dimensional reduction by pressure in the magnetic framework material CuF${}_2$(D${}_2$O)${}_2$pyz: from spin-wave to spinon excitations

Abstract

Metal organic magnets have enormous potential to host a variety of electronic and magnetic phases that originate from a strong interplay between the spin, orbital and lattice degrees of freedom. We control this interplay in the quantum magnet CuF${}_2$(D${}_2$O)${}_2$pyz by using high pressure to drive the system through a structural and magnetic phase transition. Using neutron scattering, we show that the low pressure state, which hosts a two-dimensional square lattice with spin-wave excitations and a dominant exchange coupling of 0.89 meV, transforms at high pressure into a one-dimensional spin-chain hallmarked by a spinon continuum and a reduced exchange interaction of 0.43 meV. This direct microscopic observation of a magnetic dimensional crossover as a function of pressure opens up new possibilities for studying the evolution of fractionalised excitations in low dimensional quantum magnets and eventually pressure-controlled metal--insulator transitions.

References in corpus (13)

• Critical Phenomena and Renormalization-Group Theory
• Linear spin wave theory for single-Q incommensurate magnetic structures
• Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain
• Dimensional reduction at a quantum critical point
• Neel Temperature of Quasi-Low-Dimensional Heisenberg Antiferromagnets
• Fractional excitations in the square-lattice quantum antiferromagnet
• Anomalous High-Energy Spin Excitations in La2CuO4
• Quantum and classical criticality in a dimerized quantum antiferromagnet
• The 4-spinon dynamical structure factor of the Heisenberg chain
• Spin correlations and exchange in square lattice frustrated ferromagnets
• Evolution of magnetic interactions in a pressure-induced Jahn-Teller driven magnetic dimensionality switch
• Isotope effect in quasi-two-dimensional metal-organic antiferromagnets
• Magnetic properties of the S=1/2 quasi square lattice antiferromagnet CuF2(H2O)2(pyz) (pyz=pyrazine) investigated by neutron scattering

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• One dimensionalization in the spin-1 Heisenberg model on the anisotropic triangular lattice
• Dimensional reduction in quantum spin-1/2 system on a 1/7-depleted triangular lattice
• Triplons, Magnons, and Spinons in a Single Quantum Spin System: SeCuO3
• Atacamite Cu${}_2$Cl(OH)${}_3$ in High Magnetic Fields: Quantum Criticality and Dimensional Reduction of a Sawtooth-Chain Compound
• Partially disordered Heisenberg antiferromagnet with short-range stripe correlations