Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Correlated Electrons: Spin Systems and Itinerant Magnets 1

TT 8.4: Vortrag

Montag, 25. Februar 2008, 14:45–15:00, H 0104

Gauge theory description and possible spin charge separation in itinerant chiral magnets — •Benedikt Binz and Achim Rosch — Universitaet zu Koeln

By applying pressure to the itinerant chiral magnet MnSi, a state with non-Fermi liquid electrical transport and unusual partially ordered magnetism has been observed. These experiments quite intriguingly suggest diffuse spin correlations and slow dynamics in a pure crystalline metal.

As a possible route towards a theory of the partially ordered state, we show that electrons interacting with a fluctuating magnetic background have a natural gauge theory description. We introduce new variables, where spin and charge of the conduction electrons appear separated. In this language, the helically ordered phase appears as a Anderson-Higgs phase where the gauge field is gapped and the low-energy helimagnon spectrum is obtained. It is currently not known whether this gauge theory also has (deconfined) disordered phases, which could account for the unusual behavior of MnSi under pressure.