Neutron Scattering study of Sr_2Cu_3O_4Cl_2

Abstract

We report a neutron scattering study on the tetragonal compound Sr_2Cu_3O_4Cl_2, which has two-dimensional (2D) interpenetrating Cu_I and Cu_{II} subsystems, each forming a S=1/2 square lattice quantum Heisenberg antiferromagnet (SLQHA). The mean-field ground state is degenerate, since the inter-subsystem interactions are geometrically frustrated. Magnetic neutron scattering experiments show that quantum fluctuations lift the degeneracy and cause a 2D Ising ordering of the Cu_{II} subsystem. Due to quantum fluctuations a dramatic increase of the Cu_I out-of-plane spin-wave gap is also observed. The temperature dependence and the dispersion of the spin-wave energy are quantitatively explained by spin-wave calculations which include quantum fluctuations explicitly. The values for the nearest-neighbor superexchange interactions between the Cu_I and Cu_{II} ions and between the Cu_{II} ions are determined experimentally to be J_{I-II} = -10(2)meV and J_{II}= 10.5(5)meV, respectively. Due to its small exchange interaction, J_{II}, the 2D dispersion of the Cu_{II} SLQHA can be measured over the whole Brillouin zone with thermal neutrons, and a novel dispersion at the zone boundary, predicted by theory, is confirmed. The instantaneous magnetic correlation length of the Cu_{II} SLQHA is obtained up to a very high temperature, T/J_{II}\approx 0.75. This result is compared with several theoretical predictions as well as recent experiments on the S=1/2 SLQHA.

Figures and equations are rearranged

References in corpus (2)

• Quantum Fluctuations in the Frustrated Antiferromagnet Sr_2Cu_3O_4Cl_2
• Direct Observation of the Quantum Energy Gap in S = 1/2 Tetragonal Cuprate Antiferromagnets

Cited by in corpus (26)

• Fractional excitations in the square-lattice quantum antiferromagnet
• Structural and magnetic properties of the single-layer manganese oxide La{1-x}Sr{1+x}MnO4
• Further Series Studies of the Spin-1/2 Heisenberg Antiferromagnet at T=0: Magnon Dispersion and Structure Factors
• One-dimensional magnetic fluctuations in the spin-2 triangular lattice α-NaMnO2
• Quantum vs. Geometric Disorder in a Two-Dimensional Heisenberg Antiferromagnet
• Quantum effects in a weakly-frustrated S=1/2 two-dimensional Heisenberg antiferromagnet in an applied magnetic field
• Ferroelectricity Induced by Incommensurate Magnetism
• Molecular orbital excitations in cuprates
• Quantifying entanglement with scattering experiments
• Ordered magnetism in the intrinsically decorated $j{}_{\mathrm{eff}}$ = $\frac{1}{2}$ $\alpha$-CoV${}_3$O${}_8$
• Neutron Scattering, Magnetometry, and Quantum Monte Carlo Study of the Randomly-Diluted Spin-1/2 Square-Lattice Heisenberg Antiferromagnet
• Quantum Fluctuations in the Frustrated Antiferromagnet Sr_2Cu_3O_4Cl_2
• Highly dispersive magnons with spin-gap like features in the frustrated ferromagnetic S=1/2 chain compound Ca2Y2Cu5O10 detected by inelastic neutron scattering
• Frustrated magnetic planes with intricate interaction pathways in the mineral langite Cu${}_4$(OH)${}_6$SO${}_4\cdot 2$H${}_2$O
• Two-magnon Raman scattering from the Cu3O4 layers in (Sr,Ba)2Cu3O4Cl2
• On the theory of magnetization in multiferroics: competition between ferro- and antiferromagnetic domains
• Magnetic excitations from the two-dimensional interpenetrating Cu framework in Ba${}_2$Cu${}_3$O${}_4$Cl${}_2$
• Landau Expansion for the Kugel-Khomskii $t_{2g}$ Hamiltonian
• Auxiliary-Fermion Approach to Critical Fluctuations in the 2D Quantum AF Heisenberg Model
• Magnon and Hole Excitations in the Two-Dimensional Half-filled Hubbard Model
• Direct visualization and control of antiferromagnetic domains and spin reorientation in a parent cuprate
• High-speed antiferromagnetic domain walls driven by coherent spin waves
• Neutron Scattering and magnetization studies of Ba${}_2$Cu${}_{2.95}$Co${}_{0.05}$O${}_4$Cl${}_2$: A decorated two-dimensional antiferromagnet
• Quantum corrections to the spin-wave spectrum of La${}_2$CuO${}_4$ in an external magnetic field
• Confined and deconfined spinon excitations in the rectangular-lattice quantum antiferromagnet
• Ground-state phases in a system of two competing square-lattice Heisenberg antiferromagnets