Mar 20 – 23, 2023
Campus Garching
Europe/Berlin timezone

Electron-phonon coupling in Mn$_{1-x}$Fe$_x$Si

Mar 21, 2023, 4:00 PM
Yards 4 - 6 (Fakultät für Maschinenwesen)

Yards 4 - 6

Fakultät für Maschinenwesen

Board: TU-254
Poster Magnetism, Superconductivity, Topological Systems, Magnetic Thin Films an other electronic phenomena Poster session TUESDAY


Frank Weber (Karlsruhe Institute of Technology)


The interplay of ferromagnetic exchange, Dzyaloshinsky-Moriya interaction and crystal potential results in the complex phase diagram of the chiral magnet MnSi ($T_C$ ≈ 30 K). In Mn$_{1-x}$Fe$_x$Si, long-range magnetic order is suppressed and helimagnetic correlations vanish at $x$ ≈ 0.2 along with a redistribution of d states at the Fermi energy.
Here, we present a study of the lattice dynamical properties of Mn$_{1-x}$Fe$_x$Si with 0 ≤ $x$ ≤ 0.22. Employing time-of-flight neutron spectroscopy and high energy resolution inelastic x-ray scattering, we investigate the doping dependence of phonon energies, $E_{phon}$, and line widths, $\Gamma_{phon}$ ($\Gamma_{phon} \propto$ 1/life time). In contrast to the general trend of slightly increasing energies with doping because of the reduced lattice constant, we find a significant softening and broadening of a phonon mode propagating along the [111] direction, which is also the direction of the magnetic ordering wave vector in MnSi. Ab-initio lattice dynamical calculations based on density-function theory predict an increasingly strong electron-phonon coupling for this particular mode linked to changes of the Fermi surface geometry upon doping.

Primary author

Frank Weber (Karlsruhe Institute of Technology)


Andreas Bauer (Technische Universität München) Dr Ayman Said (Argonne National Laboratory) Christian Pfleiderer Dr David Voneshen (Rutherford Appleton Laboratory) Nazir Khan (Karlsruhe Institute of Technology (KIT)) Omar de la Pena-Seaman (Benemerita Universidad Autonoma de Puebla) Rolf Heid (Karlsruhe Institute of Technology)

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