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arXiv · 1701.04730

Mutually attracting spin waves in the square-lattice quantum antiferromagnet

M. Powalski·K. P. Schmidt·G. S. Uhrig
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Abstract

The Heisenberg model for S=1/2 describes the interacting spins of electrons localized on lattice sites due to strong repulsion. It is the simplest strong-coupling model in condensed matter physics with wide-spread applications. Its relevance has been boosted further by the discovery of curate high-temperature superconductors. In leading order, their undoped parent compounds realize the Heisenberg model on square-lattices. Much is known about the model, but mostly at small wave vectors, i.e., for long-range processes, where the physics is governed by spin waves (magnons), the Goldstone bosons of the long-range ordered antiferromagnetic phase. Much less, however, is known for short-range processes, i.e., at large wave vectors. Yet these processes are decisive for understanding high-temperature superconductivity. Recent reports suggest that one has to resort to qualitatively different fractional excitations, spinons. By contrast, we present a comprehensive picture in terms of dressed magnons with strong mutual attraction on short length scales. The resulting spectral signatures agree strikingly with experimental data

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M. Powalski, K. P. Schmidt, G. S. Uhrig. 2017-01-17. Mutually attracting spin waves in the square-lattice quantum antiferromagnet. https://doi.org/10.21468/scipostphys.4.1.001

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