Abstract
We investigate the quantum Heisenberg model on the pyrochlore lattice for a generic spin S in the presence of nearest-neighbor J1 and second-nearest-neighbor J2 exchange interactions. By employing the pseudofermion functional renormalization group method, we find, for S=1/2 and S=1, an extended quantum-spin-liquid phase centered around J2=0, which is shown to be robust against the introduction of breathing anisotropy. The effects of temperature, quantum fluctuations, breathing anisotropies, and a J2 coupling on the nature of the scattering profile, and the pinch points, in particular, are studied. For the magnetic phases of the J1−J2 model, quantum fluctuations are shown to renormalize phase boundaries compared to the classical model and to modify the ordering wave vectors of spiral magnetic states, while no new magnetic orders are stabilized.18 MoreReceived 5 April 2018Revised 11 October 2018DOI:https://doi.org/10.1103/PhysRevX.9.011005Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasFrustrated magnetismQuantum spin liquidPhysical SystemsQuantum spin modelsTechniquesFunctional renormalization groupCondensed Matter, Materials & Applied Physics
Highlights
The classical nearest-neighbor Heisenberg antiferromagnet on the pyrochlore lattice stands as an epitome of geometric frustration in three dimensions as shown by its failure to develop magnetic long-range order down to absolute zero temperature, realizing what has been dubbed a “cooperative paramagnet” [1]
By employing the pseudofermion functional renormalization group method, we find, for S 1⁄4 1=2 and S 1⁄4 1, an extended quantum-spin-liquid phase centered around J2 1⁄4 0, which is shown to be robust against the introduction of breathing anisotropy
By employing pseudofermion functional renormalization group (PFFRG) for the spin-S J1-J2 Heisenberg model, we find for S 1⁄4 1=2 an extended quantum-spin-liquid regime centered around J2 1⁄4 0, with an extent of −0.25ð3Þ ≤ J2=J1 ≤ 0.22ð3Þ while, for S 1⁄4 1, its span is reduced by approximately a factor of 2, −0.11ð2Þ ≤ J2=J1 ≤ 0.09ð2Þ
Summary
The classical nearest-neighbor Heisenberg antiferromagnet on the pyrochlore lattice stands as an epitome of geometric frustration in three dimensions as shown by its failure to develop magnetic long-range order down to absolute zero temperature, realizing what has been dubbed a “cooperative paramagnet” [1]. In the low-spin-S regime, where the strong possibility of a quantum paramagnetic ground state for the nearest-neighbor quantum Heisenberg antiferromagnet exists, the impact of the above-mentioned perturbations on the paramagnet remains largely unexplored. This topic is of high significance and importance when considering the behavior of real materials.
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