Mutually attracting spin waves in the square-lattice quantum antiferromagnet
DIPC Seminars
- Speaker
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Kai Schmidt, University of Erlangen
- When
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2019/10/28
13:00 - Place
- Donostia International Physics Center
- Add to calendar
-
iCal
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 cuprate 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.
Host: Roman Orus