Spin Correlations of Quantum Spin Liquid and Quadrupole-Ordered States of Tb2+xTi2-xO7+y
Hiroaki Kadowaki, Mika Wakita, Bjorn Fak, Jacques Ollivier, Seiko Ohira-Kawamura, Kenji Nakajima, Jeffrey W. Lynn
Spin correlations of the frustrated pyrochlore oxide Tb2+xTi2-xO7+y have been investigated by using inelastic neutron scattering on single crystalline samples (x = -0.007, 0.000, and 0.003), which have the putative quantum-spin-liquid (QSL) or electric-quadrupolar ground states. Spin correlations, which are notable obeserved in nominally elastic scattering, show short-ranged correlations around L points [q = (1/2, 1/2, 1/2)], tiny antiferromagnetic Bragg scattering at L and Γ points. The short-ranged spin correlations were analyzed using a random phase approximation (RPA) assuming the paramagnetic state and two-spin interactions among Ising spins. These analyses have shown that the RPA scattering intensity well reproduces the experimental data using temperature and x dependent coupling constants of up to 10th neighbor site pairs. This suggests that no symmetry breaking occurs in the QSL sample, and that a quantum treatment beyond the semi-classical RPA approach is required. Implications of the experimental data and the RPA analyses are discussed.
, Wakita, M.
, Fak, B.
, Ollivier, J.
, Ohira-Kawamura, S.
, Nakajima, K.
and Lynn, J.
Spin Correlations of Quantum Spin Liquid and Quadrupole-Ordered States of Tb<sub>2+x</sub>Ti<sub>2-x</sub>O<sub>7+y</sub>, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926694
(Accessed December 8, 2023)