Abstract
MnSi has been extensively studied for five decades; nonetheless detailed information on the Fermi surface (FS) symmetry is still lacking. This missed information prevents a comprehensive understanding of the nature of the magnetic interaction in this material. Here, by performing angle-resolved photoemission spectroscopy on high-quality MnSi films epitaxially grown on Si(111), we unveil the FS symmetry and the evolution of the electronic structure across the paramagnetic-helimagnetic transition at , along with the appearance of sharp quasiparticle emission below . The shape of the resulting FS is found to fulfill robust nesting effects. These effects can be at the origin of strong magnetic fluctuations not accounted for by the state-of-the-art quasiparticle self-consistent approximation. From this perspective, the unforeseen quasiparticle damping detected in the paramagnetic phase and relaxing only below , along with the persistence of the -band splitting well above , at odds with a simple Stoner model for itinerant magnetism, opens the search for exotic magnetic interactions favored by FS nesting and affecting the quasiparticle lifetime.
- Received 23 September 2014
- Revised 13 April 2015
DOI:https://doi.org/10.1103/PhysRevB.92.081110
©2015 American Physical Society