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TT: Tiefe Temperaturen

TT 24: Postersitzung III: Korrelierte Elektronen, ”Orbital Physics”

TT 24.20: Poster

Mittwoch, 10. März 2004, 14:30–19:00, Poster A

The physics of chiral helices in a metal — •Inga Fischer and Achim Rosch — Institut für Theoretische Physik, Universität zu Köln

At high pressures, MnSi exhibits non-Fermi liquid behaviour over a wide temperature and pressure range [1,2]. This may point to the existence of a genuine non-Fermi liquid phase in an extremely pure cubic system. Recent neutron scattering measurements [3] suggest the presence of partial helical order in this phase, motivating us to study the physics of chiral helices theoretically.

Helical order with a large pitch is stabilized by weak spin-orbit (Dzyaloshinskii–Moriya) interactions in the non-centrosymmetric crystal structure of MnSi. The interplay of static helical order and further spin-orbit interactions in the conduction electron bands leads to the formation of surprisingly large band-gaps in certain regions of the Brillouin zone. We discuss their experimental consequences and furthermore investigate the nature of magnetic fluctuations in MnSi.

[1] C. Pfleiderer et al., Nature 414 427–430 (2001).

[2] N. Doiron-Leyraud et al., Nature 425 595–599 (2003).

[3] C. Pfleiderer et al., to be published.