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Quantum order-by-disorder and excitations in kagome-lattice magnets

Speaker: 
Sasha Chernyshev (University of California--Irvine, USA)
Date: 
Tue, 13/09/2016 - 11:00am to 12:00pm
Location: 
CA2DM Theory Common (S16-06)
Event Type: 
Seminars

Abstract:

I will discuss quantum order-by-disorder effect and will present an evidence that the non-linear terms in the anisotropic kagome-lattice antiferromagnets can yield a rare example of the ground state that is different from the one favored by thermal fluctuations. The corresponding order selection will be shown to be generated by the topologically non-trivial tunneling processes, yielding a new energy scale in the system.

I will also discuss the effect of the non-linear terms in the spectra of the kagome-lattice systems and will provide an analysis of the spectral properties of realistic kagome-lattice antiferromagnets such as Fe-jarosite, for which a remarkable wipe-out effect for a significant portion of the spectrum should exist due to a resonant-like decay processes involving two flat modes.
Recent result concerning the spectrum of the kagome-lattice ferromagnets will also be presented.

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