title: Band Structure of Helimagnons in MnSi Resolved by Inelastic Neutron Scattering.
abstract: A magnetic helix realizes a one-dimensional magnetic crystal with a period given by the pitch length λh. Its spin-wave excitations-the helimagnons-experience Bragg scattering off this periodicity, leading to gaps in the spectrum that inhibit their propagation along the pitch direction. Using high-resolution inelastic neutron scattering, the resulting band structure of helimagnons was resolved by preparing a single crystal of MnSi in a single magnetic-helix domain. At least five helimagnon bands could be identified that cover the crossover from flat bands at low energies with helimagnons basically localized along the pitch direction to dispersing bands at higher energies. In the low-energy limit, we find the helimagnon spectrum to be determined by a universal, parameter-free theory. Taking into account corrections to this low-energy theory, quantitative agreement is obtained in the entire energy range studied with the help of a single fitting parameter.
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.|Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, 85748 Garching, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kugler
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.|Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, 85748 Garching, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Brandl
authors.affiliation: Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77a, 50937 Köln, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Waizner
authors.affiliation: Condensed Matter and Magnet Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: M
authors.initials: M
authors.lastname: Janoschek
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.|Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, 85748 Garching, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Georgii
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bauer
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.|Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, 85748 Garching, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Seemann
authors.affiliation: Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77a, 50937 Köln, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Rosch
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Pfleiderer
authors.affiliation: Physik-Department E21, Technische Universität München, 85748 Garching, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Böni
authors.affiliation: Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77a, 50937 Köln, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Garst